Inter-system handover between standalone mode and non-standalone mode

ABSTRACT

Various aspects of the disclosure relate to handover of a user equipment (UE) between a standalone mode of operation and a non-standalone mode of operation. For example, a UE may be handed-over from standalone to non-standalone, or vice versa. Moreover, this handover may be an inter-system handover (e.g., between an LTE core network and an NR core network).

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of patent application Ser. No.16/534,404 filed in the U.S. Patent and Trademark Office on Aug. 7,2019. Patent application Ser. No. 16/534,404 claims priority to and thebenefit of provisional patent application No. 62/716,960 filed in theU.S. Patent and Trademark Office on Aug. 9, 2018, the entire content ofwhich is incorporated herein by reference.

INTRODUCTION

Various aspects described herein relate to wireless communication and,more particularly but not exclusively, to handing-over a user equipmentbetween a standalone mode and a non-standalone mode.

A wireless communication network may be deployed over a definedgeographical area to provide various types of services (e.g., voice,data, multimedia services, etc.) to users within that geographical area.In a typical implementation, base stations (e.g., corresponding todifferent cells) are distributed throughout a network to providewireless connectivity for user equipment (e.g., cell phones) operatingwithin the geographical area served by the network.

At a given point in time, a user equipment (UE) may be served by a givenone of these base stations. As the UE roams throughout the geographicalarea, the UE may move away from its serving base station and move closerto another base station. In addition, signal conditions within a givencell may change, whereby a UE terminal may be better served by anotherbase station. In these cases, to maintain mobility for the UE, the UEmay be handed-over from its serving base station to another basestation.

SUMMARY

The following presents a simplified summary of some aspects of thedisclosure to provide a basic understanding of such aspects. Thissummary is not an extensive overview of all contemplated features of thedisclosure, and is intended neither to identify key or critical elementsof all aspects of the disclosure nor to delineate the scope of any orall aspects of the disclosure. Its sole purpose is to present variousconcepts of some aspects of the disclosure in a simplified form as aprelude to the more detailed description that is presented later.

In one aspect, the disclosure provides an apparatus configured forcommunication that includes a processing circuit and an interfacecoupled to the processing circuit. The processing circuit is configuredto: operate in a standalone mode of operation with a first type of corenetwork associated with a first type of protocol stack; determine thatthe apparatus is to be handed-over from the standalone mode of operationto a non-standalone mode of operation; and operate in a non-standalonemode of operation with a second type of core network associated with asecond type of protocol stack as a result of the determination.

In one aspect, the disclosure provides a method of communication for anapparatus. The method includes: operating in a standalone mode ofoperation with a first type of core network associated with a first typeof protocol stack; determining that the apparatus is to be handed-overfrom the standalone mode of operation to a non-standalone mode ofoperation; and operating in a non-standalone mode of operation with asecond type of core network associated with a second type of protocolstack as a result of the determination.

In one aspect, the disclosure provides an apparatus configured forcommunication. The apparatus includes: means for operating in astandalone mode of operation with a first type of core networkassociated with a first type of protocol stack; means for determiningthat the apparatus is to be handed-over from the standalone mode ofoperation to a non-standalone mode of operation; and means for operatingin a non-standalone mode of operation with a second type of core networkassociated with a second type of protocol stack as a result of thedetermination.

In one aspect, the disclosure provides a non-transitorycomputer-readable medium storing computer-executable code, includingcode to: operate in a standalone mode of operation with a first type ofcore network associated with a first type of protocol stack; determinethat the apparatus is to be handed-over from the standalone mode ofoperation to a non-standalone mode of operation; and operate in anon-standalone mode of operation with a second type of core networkassociated with a second type of protocol stack as a result of thedetermination.

In one aspect, the disclosure provides an apparatus configured forcommunication that includes a processing circuit and an interfacecoupled to the processing circuit. The processing circuit is configuredto: determine that a user equipment is to be handed-over from astandalone mode of operation to a non-standalone mode of operation; andsend a message for handover of the user equipment from a first type ofcore network associated with a first type of protocol stack to a secondtype of core network associated with a second type of protocol stack asa result of the determination that the user equipment is to behanded-over.

In one aspect, the disclosure provides a method of communication for anapparatus. The method includes: determining that a user equipment is tobe handed-over from a standalone mode of operation to a non-standalonemode of operation; and sending a message for handover of the userequipment from a first type of core network associated with a first typeof protocol stack to a second type of core network associated with asecond type of protocol stack as a result of the determination that theuser equipment is to be handed-over.

In one aspect, the disclosure provides an apparatus configured forcommunication. The apparatus includes: means for determining that a userequipment is to be handed-over from a standalone mode of operation to anon-standalone mode of operation; and means for sending a message forhandover of the user equipment from a first type of core networkassociated with a first type of protocol stack to a second type of corenetwork associated with a second type of protocol stack as a result ofthe determination that the user equipment is to be handed-over.

In one aspect, the disclosure provides a non-transitorycomputer-readable medium storing computer-executable code, includingcode to: determine that a user equipment is to be handed-over from astandalone mode of operation to a non-standalone mode of operation; andsend a message for handover of the user equipment from a first type ofcore network associated with a first type of protocol stack to a secondtype of core network associated with a second type of protocol stack asa result of the determination that the user equipment is to behanded-over.

These and other aspects of the disclosure will become more fullyunderstood upon a review of the detailed description, which follows.Other aspects, features, and implementations of the disclosure willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific implementations of the disclosurein conjunction with the accompanying figures. While features of thedisclosure may be discussed relative to certain implementations andfigures below, all implementations of the disclosure can include one ormore of the advantageous features discussed herein. In other words,while one or more implementations may be discussed as having certainadvantageous features, one or more of such features may also be used inaccordance with the various implementations of the disclosure discussedherein. In similar fashion, while certain implementations may bediscussed below as device, system, or method implementations it shouldbe understood that such implementations can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description ofaspects of the disclosure and are provided solely for illustration ofthe aspects and not limitations thereof.

FIG. 1 is a diagram illustrating an example communication system withinwhich aspects of the disclosure may be implemented.

FIG. 2 is a diagram illustrating an example of standalone (SA) tonon-standalone (NSA) handover.

FIG. 3 is a message flow diagram illustrating an example of SA to NSAhandover in accordance with some aspects of the disclosure.

FIG. 4 is a message flow diagram illustrating another example of SA toNSA handover in accordance with some aspects of the disclosure.

FIG. 5 is a message flow diagram illustrating an example of NSA to SAhandover in accordance with some aspects of the disclosure.

FIG. 6 is a block diagram illustrating an example hardwareimplementation for an apparatus (e.g., an electronic device) that cansupport communication in accordance with some aspects of the disclosure.

FIG. 7 is a flowchart illustrating an example of a handover process inaccordance with some aspects of the disclosure.

FIG. 8 is a flowchart illustrating example operations that may beperformed, for example, in conjunction with the handover process of FIG.7 in accordance with some aspects of the disclosure.

FIG. 9 is a block diagram illustrating an example hardwareimplementation for another apparatus (e.g., an electronic device) thatcan support communication in accordance with some aspects of thedisclosure.

FIG. 10 is a flowchart illustrating another example of a handoverprocess in accordance with some aspects of the disclosure.

FIG. 11 is a flowchart illustrating example operations that may beperformed, for example, in conjunction with the handover process of FIG.10 in accordance with some aspects of the disclosure.

FIG. 12 is a block diagram illustrating an example hardwareimplementation for another apparatus (e.g., an electronic device) thatcan support communication in accordance with some aspects of thedisclosure.

FIG. 13 is a flowchart illustrating another example of a handoverprocess in accordance with some aspects of the disclosure.

FIG. 14 is a block diagram illustrating an example hardwareimplementation for another apparatus (e.g., an electronic device) thatcan support communication in accordance with some aspects of thedisclosure.

FIG. 15 is a flowchart illustrating another example of a handoverprocess in accordance with some aspects of the disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure relate to handover of a UE between astandalone mode of operation and a non-standalone mode of operation. Forexample, the disclosure relates in some aspects to defining a UEcapability for inter-system handover from a 5G new radio (NR) standalonemode of operation to an E-UTRAN NR—dual connectivity (EN-DC) mode ofoperation.

In a standalone mode of operation, a device (e.g., a UE) uses a singleradio access technology (RAT). Three standalone options are defined bythe 3rd Generation Partnership Project (3GPP). Option 1 involves 4Gevolved packet core (EPC) and 3GPP Long-Term Evolution (LTE) eNB access(e.g., as in a 4G LTE network). Option 2 involves 5G core network (5GC)and New Radio (NR) gNB access. Option 5 involves 5GC and LTE NextGeneration-eNB (ng-eNB) access.

In a non-standalone mode of operation, a device (e.g., a UE) usesmultiple radio access technologies (RATs). Three non-standalone optionsare defined by 3GPP. Option 3 involves using EPC and an LTE eNB actingas a master base station and an NR en-gNB acting as a secondary basestation. Option 4 involves 5GC and NR gNB access. Option 5 involves 5GCand ng-eNB access.

Intra-system handover from a standalone (SA) mode of operation to anon-standalone (NSA) mode of operation is a known concept. For example,section 10.9 of the 3GPP specification TS 37.340 defines intra-system SAto NSA handover for a 5G scenario.

However, an inter-system SA to NSA handover (or vice versa) may also beuseful in some scenarios. In some aspects, inter-system (e.g.,inter-RAT) handover refers to handover between different types of corenetworks (e.g., between a 4G evolved packet core (EPC) core network anda 5G core network, 5GC). For example, SA to NSA handover may be used inEvolved Packet System (EPS) fallback scenarios, such as Option 2 (NRconnected to 5G core network, 5GC) to Option 3 (E-UTRAN NR—dualconnectivity. EN-DC) handover. As a specific example, when a UE with anongoing high-performance demand data service needs to perform a mobileoriented (MO) or mobile terminated (MT) voice call but Voice over NR(VoNR) is not supported, falling-back to EPS and keeping NR as thesecondary node (SN) may help to preserve a good user experience (e.g.,by maintaining ongoing data service).

The following issues may arise from the UE point of view in supportinginter-system (e.g., inter-RAT) handover from a NR standalone mode ofoperation to an EN-DC mode of operation. The NR protocol stack maychange the role from “master with 5GC connection” to “secondary with EPCconnection.” The NR protocol stack may sustain the aforementioned“master” role and “secondary” role during inter-system handover so itcan roll back to the source configuration in case of handover failure.The disclosure relates in some aspects to handling these and/or otherissues that may be associated with inter-system SA to NSA handover, aswell as inter-system NSA to SA handover.

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. Moreover, alternate configurations may be devised withoutdeparting from the scope of the disclosure. Additionally, well-knownelements will not be described in detail or will be omitted so as not toobscure the relevant details of the disclosure.

The various concepts presented throughout this disclosure may beimplemented across a broad variety of telecommunication systems, networkarchitectures, and communication standards. For example, the 3rdGeneration Partnership Project (3GPP) is a standards body that definesseveral wireless communication standards for networks involving theevolved packet system (EPS), frequently referred to as long-termevolution (LTE) networks. Evolved versions of the LTE network, such as afifth-generation (5G) network, may provide for many different types ofservices or applications, including but not limited to web browsing,video streaming, VoIP, mission critical applications, multi-hopnetworks, remote operations with real-time feedback (e.g.,tele-surgery), etc. Thus, the teachings herein can be implementedaccording to various network technologies including, without limitation,5G technology, fourth generation (4G) technology, third generation (3G)technology, and other network architectures. Thus, various aspects ofthe disclosure may be extended to networks based on 3rd GenerationPartnership Project (3GPP) Long Term Evolution (LTE). LTE-Advanced(LTE-A) (in FDD, TDD, or both modes), Universal MobileTelecommunications System (UMTS), Global System for MobileCommunications (GSM), Code Division Multiple Access (CDMA),Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB),Bluetooth, and/or other suitable systems. Also, the techniques describedherein may be used for a downlink, an uplink, a peer-to-peer link, orsome other type of link.

The actual telecommunication standard, network architecture, and/orcommunication standard used will depend on the specific application andthe overall design constraints imposed on the system. For purposes ofillustration, the following may describe various aspects in the contextof a 5G system and/or an LTE system. It should be appreciated, however,that the teachings herein may be used in other systems as well. Thus,references to functionality in the context of 50 and/or LTE terminologyshould be understood to be equally applicable to other types oftechnology, networks, components, signaling, and so on.

Example Communication System

FIG. 1 illustrates an example of a wireless communication system 100where a user equipment (UE) can communicate with other devices viawireless communication signaling. For example, a first UE 102A and asecond UE 102B may communicate with a first cell 104 (e.g., an LTE basestation), a second cell 106 (e.g., an NR base station), some other cell,or a combination thereof, using wireless communication resources managedby the first cell 104, the second cell 106, other network components(e.g., a core network 108, an internet service provider (ISP) 110, peerdevices, and so on), or a combination thereof. In some implementations,one or more of the components of the system 100 may communicate witheach other directedly via a device-to-device (D2D) link 112 or someother similar type of direct link.

Communication of information between two or more of the components ofthe system 100 may result in a handover from one cell to another. Forexample, the second UE 102B may be handed-over from the second cell 106to the first cell 104, or vice versa. In accordance with the teachingsherein, one or more of the first UE 102A, the second UE 102B, or someother component of the system 100 may include a module for SA/NSAhandover 114. In accordance with the teachings herein, one or more ofthe first cell 104, the second cell 106, or some other component of thesystem 100 may include a module for SA/NSA handover 116.

The components and links of the wireless communication system 100 maytake different forms in different implementations. For example, andwithout limitation, UEs may be cellular devices, Internet of Things (I)devices, cellular IoT (CloT) devices, LTE wireless cellular devices,machine-type communication (MTC) cellular devices, smart alarms, remotesensors, smart phones, mobile phones, smart meters, personal digitalassistants (PDAs), personal computers, mesh nodes, and tablet computers.

In some aspects, a TRP may refer to a physical entity that incorporatesradio head functionality for a particular physical cell. In someaspects, the TRP may include 5G new radio (NR) functionality with an airinterface based on orthogonal frequency division multiplexing (OFDM). NRmay support, for example and without limitation, enhanced mobilebroadband (eMBB), mission-critical services, and wide-scale deploymentof IoT devices. The functionality of a TRP may be similar in one or moreaspects to (or incorporated into) the functionality of a CloT basestation (C-BS), a NodeB, an evolved NodeB (eNodeB), radio access network(RAN) access node, a radio network controller (RNC), a base station(BS), a radio base station (RBS), a base station controller (BSC), abase transceiver station (BTS), a transceiver function (TF), a radiotransceiver, a radio router, a basic service set (BSS), an extendedservice set (ESS), a macro cell, a macro node, a Home eNB (HeNB), afemto cell, a femto node, a pico node, or some other suitable entity. Indifferent scenarios (e.g., NR, LTE, etc.), a TRP may be referred to as agNodeB (gNB), an eNB, a base station, or referenced using otherterminology.

Various types of network-to-device links and D2D links may be supportedin the wireless communication system 100. For example, D2D links mayinclude, without limitation, machine-to-machine (M2M) links, MTC links,vehicle-to-vehicle (V2V) links, vehicle-to-anything (V2X) links, andcellular V2X (CV2X) links. Network-to-device links may include, withoutlimitation, uplinks (or reverse links), downlinks (or forward links),and vehicle-to-network (V2N) links.

Example SA/NSA Handover

FIG. 2 is a schematic illustration of a wireless communication system200 where a UE 202 may be handed-over from an SA mode to an NSA mode, orvice versa. The wireless communication system 200 includes a first corenetwork 204 (e.g., an LTE network) and a second core network 206 (e.g.,an NR network), and potentially other networks (not shown).

In the example, of FIG. 2 , the UE 202 may operate in a SA mode 208whereby the UE 202 is initially connected to a source base station 210(e.g., an eNB or a gNB) of the second core network 206. At some point intime, the UE 202 may be subject to an inter-network SA to NSA handover212 (e.g., to obtain a service via the another network).

In the example of FIG. 2 , in an NSA mode 214, the UE 202 may connect toa master base station 216 (e.g., an eNB) in the first core network 204and a secondary base station (e.g., a gNB) 218 in the second corenetwork 206. As discussed herein, in some scenarios, the source basestation 210 rather than the base station 218 may be designated as thesecondary base station for the NSA mode.

In some implementations, the source base station 210 may correspond tothe second cell 106 (e.g., a transmit receive point, a base station,etc.) or some other component of FIG. 1 . In some implementations, themaster base station 216 may correspond to the first cell 104 (e.g., atransmit receive point, a base station, etc.) or some other component ofFIG. 1 . In some implementations, the UE 202 may correspond to the firstUE 102A, the second UE 102B, or some other component of FIG. 1 .

Use Cases of Inter-System Handover Between SA and NSA

SA to NSA inter-system handover may include for, example. Option 2(NR/5GC) to Option 3 (EN-DC) handover as well as Option 5 (LTE/5GC) toOption 3 (EN-DC) handover. Option 2 to Option 3 handover may beparticularly useful. For example, when a UE with an ongoinghigh-performance demand data service needs to perform a mobile oriented(MO) or mobile terminated (MT) voice call but Voice over NR (VoNR) isnot supported by the NR core network, the UE may fall-back to an EPScore network for the voice call while keeping the NR core network as thesecondary node (SN) to preserve a good user experience (e.g., bymaintaining the ongoing high-performance data service on the NR corenetwork).

NSA to SA inter-system handover includes the reverse of the abovescenarios. Again, using voice fallback as an example, after the voicecall ends, the network may handover the UE from NSA Option 3 to SAOption 2 to save UE power. In the handover, it is possible that thetarget node doesn't support DC. Thus, the UE will go back to a SA modeof operation.

Option 2/5 to Option 3 Handover Procedure

FIG. 3 illustrates an example of signaling for an Option 2/5 to Option 3handover procedure 300 (e.g., an NR/5GC to EN-DC Handover Procedure).Here, Option 2/5 to Option 3 handover may include Option 2 to Option 3handover and/or Option 5 to Option 3 handover.

In this example, a UE 302 is initially connected to a source basestation in an SA mode of operation. The source base station isdesignated as a Source Next Generation (NG) eNB or gNB (S-ng-eNB/gNB304) in FIG. 3 . The source base station could take other forms in otherimplementations. The UE 302 is subsequently handed-over to a target basestation. The target base station is designated as a Target Master eNB(MeNB) (Target MeNB 306). The target base station could take other formsin other implementations.

At step 1, the S-ng-eNB/gNB 304 starts the handover by initiating aHandover Required procedure (e.g., a Next Generation (NG) HandoverRequired procedure). For example, the S-ng-eNB/gNB 304 may determinethat the UE 302 needs a service (e.g., VoNR) that is not supported bythe SA mode of operation.

At step 2, an access and mobility management function (AMF) of the 5GC(designated AMF/5GC 308) sends a Forward Relocation Request to thetarget mobility management entity (designated MME 310). The MME 310starts to create a session on the serving gateway (designated SGW 312).

At step 3, the MME 310 sends a Handover Request to the Target MeNB 306for EN-DC. The Target MeNB 306 determines whether to handover to EN-DC(e.g., based on whether DC is supported by the UE 302 and measurementreports from the UE 302). If handover is indicated, the Target MeNB 306sends an SgNB Addition Request to the Target SN at step 4. At step 5,the Target SN 314 replies with an SgNB Addition Request Ack. At step 6,the target MeNB 306 replies to the MME 310 with a Handover Request Ack(e.g., including the new configuration information for the UE 302 andthe Target SN 314, such as protocol stack information and DCconfiguration). At step 7, the MME 310 replies to the AMF/5GC 308 with aRelocation Request Ack. At step 8, the AMF/5GC 308 sends a HandoverCommand to the S-ng-eNB/gNB 304.

At step 9, the S-ng-eNB/gNB 304 triggers the UE 302 to perform thehandover and apply the new configuration. For example, the UE 302 mayswitch from a 5G protocol stack to a 40 protocol stack (e.g., where the40 and 5G protocol stacks support different types of QoSs) and configureDC (e.g., to accommodate the DC master and secondary roles).

At step 10, the UE 302 synchronizes to the Target MeNB 306 (e.g., byconducting a random access procedure). At step 11, the UE 302 replies tothe Target MeNB 306 with RRC Connection Reconfiguration completemessage. At step 12, the UE 302 synchronizes to the Target SN 314 (e.g.,by conducting a random access procedure). At step 13, if the RRCconnection reconfiguration procedure was successful, the Target MeNB 306informs the Target SN 314 via an SgNB Reconfiguration Complete message.

The system may then perform data forwarding operations 316, contextrelease operations 318, tracking area update operations 320, and otheroperations as needed.

In some implementations, the S-ng-eNB/gNB 304 may correspond to thesecond cell 106 (e.g., a transmit receive point, a base station, etc.)or some other component of FIG. 1 . In some implementations, the targetMeNB 306 may correspond to the first cell 104 (e.g., a transmit receivepoint, a base station, etc.) or some other component of FIG. 1 . In someimplementations, the UE 302 may correspond to the first UE 102A, thesecond UE 102B, or some other component of FIG. 1 .

Impact on Data Service

In some aspects, the procedure of FIG. 3 may impact (e.g., interrupt) anongoing data service. Several examples of the operations that may impactan ongoing data service include: 1) RF/PHY tuning from a source gNB to atarget SgNB/MeNB; 2) Random access and Media Access Control, Radio LinkControl, Packet Data Convergence Protocol (MAC/RLC/PDCP)re-establishment in the target SN; and 3) Data forwarding (e.g.,gNB→MeNB→Target SN).

Alternative Handover Procedure

FIG. 4 illustrates an example of a handover procedure 400 that maymitigate (e.g., avoid) the impact on data service. In this example, thesource gNB is selected as the target SN. Consequently, RF/PHY tuning,random access and MAC/RLC/PDCP re-establishment, the data forwardingassociated with selecting the target SN might not be needed.

In this example, a UE 402 is initially connected to a source basestation in an SA mode of operation. The source base station isdesignated as a Source gNB 404 in FIG. 4 . The source base station couldtake other forms in other implementations. The UE 402 is subsequentlyhanded-over to a target base station. The target base station isdesignated as a Target eNB 406. The target base station could take otherforms in other implementations.

At step 1, the Source gNB 404 starts the handover procedure byinitiating the Handover Required procedure. In this case, to induce theTarget eNB 406 to select the Source gNB 404 as the target SN, the SourcegNB 404 may include both an NR measurement result (e.g.,candidateCellInfoListNR-r15) and candidate E-UTRA cell information inthe RRC container of an NG-AP Handover Required message. The Source gNB404 could also send a “false” measurement report (e.g., that lists theTarget eNB 406 as having the best signal quality) so that the Target eNB406 will select the Source gNB 404 as the target SN.

At step 2, the AMF/5GC 408 sends a Relocation Request to the target MME410. The MME 410 starts to create a session on the SGW 412. At step 3,the MME 410 sends a Handover Request to the Target eNB 406. Thus, theTarget eNB 406 may receive the RRC container of an NG-AP HandoverRequired message from step 1. At step 4, the Target eNB 406 sends anSgNB Addition Request to the Source gNB 404 which has been selected asthe Target SN. For example, based on one or more of the QoS profile ofthe enhanced radio access bearers (E-RABs) (e.g., forwarded by step 2and step 3), the DC capability of the UE 402, the NR measurement result,local policy, or a combination thereof, the Target eNB 406 may decide toconfigure the target SgNB for the UE 402. The Source gNB 404 may bepreferred here based on the NR measurement result in step 1.

To reduce impact to the ongoing data service in NR, one or more offollowing optimizations may be performed. For data forwarding, theTarget eNB 406 may elect to keep the existing data radio bearers (DRBs)in the Source gNB 404. Thus, an MeNB might not have DRB/E-RAB in thiscase. For security, the Target eNB 406 may elect to not apply thesecurity key change for an SgNB to avoid L2 protocol re-establishment.This may involve the use of an appropriate indicator in step 4 and step9 to inform the Source gNB 404 and the UE 402, respectively.

At step 5, the Target SN replies with an SgNB Addition Request Ack. Atstep 6, the Target eNB 406 replies to the MME 410 with a HandoverRequest Ack. At step 7, the MME 410 replies to the AMF/5GC 408 with aRelocation Request Ack. At step 8, the AMF/5GC 408 sends a HandoverCommand to the Source gNB 404. At step 9, the Source gNB 404 triggersthe UE 402 to perform the handover and apply the new configuration.

At step 10, the UE 402 synchronizes to the Target eNB 406 (e.g., byconducting a random access procedure). At step 11, the UE 402 replies tothe Target eNB 406 with an eNB RRC Connection Reconfiguration completemessage. Of note, the UE 402 does not need to synchronize to the TargetSN in this procedure since the Source gNB 404 is the target SN.

At step 12, if the RRC connection reconfiguration procedure wassuccessful, the Target eNB 406 informs the Target SN of this via an SgNBReconfiguration Complete message. The system may then perform dataforwarding operations 414, tracking area update operations 416, andother operations as needed.

The above procedure can be further optimized to further reduce thehandover latency. For example, in step 1, the Handover Required messagemay include a flag to indicate that this is an Option-2-SA toOption-EN-DC handover where the Source-gNB is to be selected as the SNfor EN-DC. As another example, steps 4 and 5 (SgNB-Addition-Request andSgNB Addition Request Ack) can be removed. In this case, the RRCconfiguration information that would be delivered in step 4 can beincluded in steps 6, 7, and 8 and sent to the UE 402 by the Source gNB404 in step 9.

In some implementations, the Source gNB 404 may correspond to the secondcell 106 (e.g., a transmit receive point, a base station, etc.) or someother component of FIG. 1 . In some implementations, the Target eNB 406may correspond to the first cell 104 (e.g., a transmit receive point, abase station, etc.) or some other component of FIG. 1 . In someimplementations, the UE 402 may correspond to the first UE 102A, thesecond UE 102B, or some other component of FIG. 1 .

Option 3 to Option 2/5 Inter-System Handover

FIG. 5 illustrates an example of an Option 3 to Option 2/5 handoverprocedure 500. In this example, a UE 502 is initially connected to asource base station in an SA mode of operation. The source base stationis designated as a Serving Master Node (S-MN 504) in FIG. 5 . The sourcebase station could take other forms in other implementations. The UE 502is subsequently handed-over to a target base station. The target basestation is designated as a target Next Generation (NG) eNB or gNB(T-ng-eNB/gNB 506). The target base station could take other forms inother implementations

At step 1, the S-MN 504 starts the handover procedure by initiating theHandover Required procedure. Thus, in this example, the S-MN 504determines that it will initiate an inter-system (e.g., inter-network)handover (e.g., the S-MN 504 may initiate an NSA to SA handover,switching from a 4G network to a 5G network). The handover decision maybe based, for example, on the service that caused the Option 2/5 toOption 3 handover having ended (e.g., a VoNR session ended).

At step 2, an MME 508 sends a Relocation Request to an AMF 510. At step3, the AMF 510 sends a Handover Request to a Serving Secondary Node(S-SN 512). At step 4, the S-SN 512 replies to the AMF 510 with aHandover Request Ack. At step 5, the AMF 510 replies to the MME 508 witha Relocation Request Ack. At step 6, the MME 508 sends a HandoverCommand to the S-MN 504.

The handover procedure 500 may then involve performing any required RRCconnection reconfiguration, random access. SN status transfer, dataforwarding, and secondary RAT reporting procedures 516. For example, theprocedure 516 may include operations similar to steps 9 11 of FIG. 4 .In addition, for SN terminated bearers, the S-SN 512 may send a SNStatus transfer to the S-MN 504, which the S-MN 504 then sends to theT-ng-eNB/gNB 506. Also, if applicable, the procedure 516 may includedata forwarding from the S-SN 512. In addition, the S-SN 512 sends theSecondary RAT Data Volume Report message to the S-MN 504 and includesthe data volumes delivered to the UE 502 over the NR radio for therelated E-RABs. The S-MN 504 then sends the Secondary RAT Report messageto the MME 508 to provide information on the used NR resource. Finally,a registration request procedure 518 is performed to register the UE 502with the 5G system and establish user context in the 5G system.

In some implementations, the T-ng-eNB/gNB 506 may correspond to thesecond cell 106 (e.g., a transmit receive point, a base station, etc.)or some other component of FIG. 1 . In some implementations, the S-MN504 may correspond to the first cell 104 (e.g., a transmit receivepoint, a base station, etc.) or some other component of FIG. 1 . In someimplementations, the UE 502 may correspond to the first UE 102A, thesecond UE 102B, or some other component of FIG. 1 .

Example UE Operations

As part of the handover procedure, the UE may maintain both the NSAcontext (e.g., associated with source) and the SA context (e.g.,associated with the target). This will enable the UE to return to theoriginal cell and revert to the original configuration in the event of ahandover failure.

In some implementations, the UE may indicate (e.g., via UE Capabilitiesor via some other indication) whether the UE supports SA/NSA handover.Thus, the network may use this information to determine whether tohandover the UE (e.g., from SA to NSA).

Example Optimizations

As discussed above, one or more optimizations may be used in conjunctionwith the procedures described herein. In EPS fallback with a highquality of service (QoS) demand data service, the source gNB may includeboth an LTE measurement result and an NR measurement result (ormeasurement information from other RATs or core networks) in the RRCContainer of Handover Required message. Signaling may be defined toallow a gNB and a UE to use a previous security key in NR. For example,a no-key-update indicator may be included in an RRC ConnectionReconfiguration message and/or in an SgNB Addition Request message.Random access to the source gNB may be skipped if the source gNB isselected as the target SN. A source gNB to target SN handover indicatormay be included in an NG-AP Handover Required message (e.g., to enablethe source gNB to explicitly request the optimized Option 2 to Option 3handover). The SgNB-Addition-Request and the SgNB-Addition-Request-Ackmay be omitted, whereby the related RRC configuration information isinstead sent in a handover command or some other command.

First Example Apparatus

FIG. 6 illustrates a block diagram of an example hardware implementationof an apparatus 600 configured to communicate according to one or moreaspects of the disclosure. The apparatus 600 could embody or beimplemented within a UE, a gNB, a transmit receive point (TRP), a basestation (BS), an eNode B (eNB), a CPE, or some other type of device thatsupports wireless communication. In various implementations, theapparatus 600 could embody or be implemented within an access terminal,an access point, or some other type of device. In variousimplementations, the apparatus 600 could embody or be implemented withina server, a personal computer, a mobile phone, a smart phone, a tablet,a portable computer, a sensor, an alarm, a vehicle, a machine, anentertainment device, a medical device, or any other electronic devicehaving circuitry.

The apparatus 600 includes a communication interface (e.g., at least onetransceiver) 602, a storage medium 604, a user interface 606, a memorydevice (e.g., a memory circuit) 608, and a processing circuit 610 (e.g.,at least one processor). In various implementations, the user interface606 may include one or more of: a keypad, a display, a speaker, amicrophone, a touchscreen display, of some other circuitry for receivingan input from or sending an output to a user.

These components can be coupled to and/or placed in electricalcommunication with one another via a signaling bus or other suitablecomponent, represented generally by the connection lines in FIG. 6 . Thesignaling bus may include any number of interconnecting buses andbridges depending on the specific application of the processing circuit610 and the overall design constraints. The signaling bus links togethervarious circuits such that each of the communication interface 602, thestorage medium 604, the user interface 606, and the memory device 608are coupled to and/or in electrical communication with the processingcircuit 610. The signaling bus may also link various other circuits (notshown) such as timing sources, peripherals, voltage regulators, andpower management circuits, which are well known in the art, andtherefore, will not be described any further.

The communication interface 602 provides a means for communicating withother apparatuses over a transmission medium. In some implementations,the communication interface 602 includes circuitry and/or programmingadapted to facilitate the communication of information bi-directionallywith respect to one or more communication devices in a network. In someimplementations, the communication interface 602 is adapted tofacilitate wireless communication of the apparatus 600. In theseimplementations, the communication interface 602 may be coupled to oneor more antennas 612 as shown in FIG. 6 for wireless communicationwithin a wireless communication system. In some implementations, thecommunication interface 602 may be configured for wire-basedcommunication. For example, the communication interface 602 could be abus interface, a send/receive interface, or some other type of signalinterface including drivers, buffers, or other circuitry for outputtingand/or obtaining signals (e.g., outputting signal from and/or receivingsignals into an integrated circuit). The communication interface 602 canbe configured with one or more standalone receivers and/or transmitters,as well as one or more transceivers. In the illustrated example, thecommunication interface 602 includes a transmitter 614 and a receiver616. The communication interface 602 serves as one example of a meansfor receiving and/or means transmitting.

The memory device 608 may represent one or more memory devices. Asindicated, the memory device 608 may maintain handover information 618along with other information used by the apparatus 600. In someimplementations, the memory device 608 and the storage medium 604 areimplemented as a common memory component. The memory device 608 may alsobe used for storing data that is manipulated by the processing circuit610 or some other component of the apparatus 600.

The storage medium 604 may represent one or more computer-readable,machine-readable, and/or processor-readable devices for storingprogramming, such as processor executable code or instructions (e.g.,software, firmware), electronic data, databases, or other digitalinformation. The storage medium 604 may also be used for storing datathat is manipulated by the processing circuit 610 when executingprogramming. The storage medium 604 may be any available media that canbe accessed by a general purpose or special purpose processor, includingportable or fixed storage devices, optical storage devices, and variousother mediums capable of storing, containing or carrying programming.

By way of example and not limitation, the storage medium 604 may includea magnetic storage device (e.g., hard disk, floppy disk, magneticstrip), an optical disk (e.g., a compact disc (CD) or a digitalversatile disc (DVD)), a smart card, a flash memory device (e.g., acard, a stick, or a key drive), a random access memory (RAM), a readonly memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM),an electrically erasable PROM (EEPROM), a register, a removable disk,and any other suitable medium for storing software and/or instructionsthat may be accessed and read by a computer. The storage medium 604 maybe embodied in an article of manufacture (e.g., a computer programproduct). By way of example, a computer program product may include acomputer-readable medium in packaging materials. In view of the above,in some implementations, the storage medium 604 may be a non-transitory(e.g., tangible) storage medium. For example, the storage medium 604 maybe a non-transitory computer-readable medium storing computer-executablecode, including code to perform operations as described herein.

The storage medium 604 may be coupled to the processing circuit 610 suchthat the processing circuit 610 can read information from, and writeinformation to, the storage medium 604. That is, the storage medium 604can be coupled to the processing circuit 610 so that the storage medium604 is at least accessible by the processing circuit 610, includingexamples where at least one storage medium is integral to the processingcircuit 610 and/or examples where at least one storage medium isseparate from the processing circuit 610 (e.g., resident in theapparatus 600, external to the apparatus 600, distributed acrossmultiple entities, etc.).

Programming stored by the storage medium 604, when executed by theprocessing circuit 610, causes the processing circuit 610 to perform oneor more of the various functions and/or process operations describedherein. For example, the storage medium 604 may include operationsconfigured for regulating operations at one or more hardware blocks ofthe processing circuit 610, as well as to utilize the communicationinterface 602 for wireless communication utilizing their respectivecommunication protocols.

The processing circuit 610 is generally adapted for processing,including the execution of such programming stored on the storage medium604. As used herein, the terms “code” or “programming” shall beconstrued broadly to include without limitation instructions,instruction sets, data, code, code segments, program code, programs,programming, subprograms, software modules, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, etc., whetherreferred to as software, firmware, middleware, microcode, hardwaredescription language, or otherwise.

The processing circuit 610 is arranged to obtain, process and/or senddata, control data access and storage, issue commands, and control otherdesired operations. The processing circuit 610 may include circuitryconfigured to implement desired programming provided by appropriatemedia in at least one example. For example, the processing circuit 610may be implemented as one or more processors, one or more controllers,and/or other structure configured to execute executable programming.Examples of the processing circuit 610 may include a general purposeprocessor, a digital signal processor (DSP), an application-specificintegrated circuit (ASIC), a field programmable gate array (FPGA) orother programmable logic component, discrete gate or transistor logic,discrete hardware components, or any combination thereof designed toperform the functions described herein. A general purpose processor mayinclude a microprocessor, as well as any conventional processor,controller, microcontroller, or state machine. The processing circuit610 may also be implemented as a combination of computing components,such as a combination of a DSP and a microprocessor, a number ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, an ASIC and a microprocessor, or any other number of varyingconfigurations. These examples of the processing circuit 610 are forillustration and other suitable configurations within the scope of thedisclosure are also contemplated.

According to one or more aspects of the disclosure, the processingcircuit 610 may be adapted to perform any or all of the features,processes, functions, operations and/or routines for any or all of theapparatuses described herein. For example, the processing circuit 610may be configured to perform any of the steps, functions, and/orprocesses described with respect to FIGS. 1-5, 7, and 8 . As usedherein, the term “adapted” in relation to the processing circuit 610 mayrefer to the processing circuit 610 being one or more of configured,employed, implemented, and/or programmed to perform a particularprocess, function, operation and/or routine according to variousfeatures described herein.

The processing circuit 610 may be a specialized processor, such as anapplication-specific integrated circuit (ASIC) that serves as a meansfor (e.g., structure for) carrying out any one of the operationsdescribed in conjunction with FIGS. 1-5, 7, and 8 . The processingcircuit 610 serves as one example of a means for transmitting and/or ameans for receiving. In some implementations, the processing circuit 610may provide and/or incorporate, at least in part, the functionality ofone or more of the system components described herein (e.g., the modulefor SA/NSA handover 114 of FIG. 1 ).

According to at least one example of the apparatus 600, the processingcircuit 610 may include one or more of a circuit/module for operating620, a circuit/module for determining that a UE is to be handed-over622, a circuit/module for obtaining 624, a circuit/module formaintaining 626, a circuit/module for determining that handover failed628, a circuit/module for reverting 630, a circuit/module for using 632,a circuit/module for receiving 634, a circuit/module for acquiring 636,a circuit/module for sending 638, a circuit/module for determining thata source base station is a secondary base station 640, or acircuit/module for electing 642. In various implementations, thecircuit/module for operating 620, the circuit/module for determiningthat a UE is to be handed-over 622, the circuit/module for obtaining624, the circuit/module for maintaining 626, the circuit/module fordetermining that handover failed 628, the circuit/module for reverting630, the circuit/module for using 632, the circuit/module for receiving634, the circuit/module for acquiring 636, the circuit/module forsending 638, the circuit/module for determining that a source basestation is a secondary base station 640, or the circuit/module forelecting 642 may provide and/or incorporate, at least in part, thefunctionality of one or more of the system components described herein(e.g., the module for SA/NSA handover 114 of FIG. 1 ).

As mentioned above, programming stored by the storage medium 604, whenexecuted by the processing circuit 610, causes the processing circuit610 to perform one or more of the various functions and/or processoperations described herein. For example, the programming may cause theprocessing circuit 610 to perform the various functions, steps, and/orprocesses described herein with respect to FIGS. 1-5, 7, and 8 invarious implementations. As shown in FIG. 6 , the storage medium 604 mayinclude one or more of code for operating 650, code for determining thata UE is to be handed-over 652, code for obtaining 654, code formaintaining 656, code for determining that handover failed 658, code forreverting 660, code for using 662, code for receiving 664, code foracquiring 666, code for sending 668, code for determining that a sourcebase station is a secondary base station 670, or code for electing 672.In various implementations, the code for operating 650, the code fordetermining that a UE is to be handed-over 652, the code for obtaining654, the code for maintaining 656, the code for determining thathandover failed 658, the code for reverting 660, the code for using 662,the code for receiving 664, the code for acquiring 666, the code forsending 668, the code for determining that a source base station is asecondary base station 670, or the code for electing 672 may be executedor otherwise used to provide the functionality described herein for thecircuit/module for operating 620, the circuit/module for determiningthat a UE is to be handed-over 622, the circuit/module for obtaining624, the circuit/module for maintaining 626, the circuit/module fordetermining that handover failed 628, the circuit/module for reverting630, the circuit/module for using 632, the circuit/module for receiving634, the circuit/module for acquiring 636, the circuit/module forsending 638, the circuit/module for determining that a source basestation is a secondary base station 640, or the circuit/module forelecting 642.

The circuit/module for operating 620 may include circuitry and/orprogramming (e.g., code for operating 650 stored on the storage medium604) adapted to perform several functions relating to, for example,operating in a particular mode of operation as discussed herein (e.g.,based on a determination that the mode of operation provides a requestservice, etc.). In some aspects, the circuit/module for operating 620(e.g., a means for operating) may correspond to, for example, aprocessing circuit.

The circuit/module for determining that a UE is to be handed-over 622may include circuitry and/or programming (e.g., code for determiningthat a UE is to be handed-over 652 stored on the storage medium 604)adapted to perform several functions relating to, for example,determining that handover is indicated as discussed herein (e.g., basedon a handover trigger, etc.). In some aspects, the circuit/module fordetermining that a UE is to be handed-over 622 (e.g., a means fordetermining that a UE is to be handed-over) may correspond to, forexample, a processing circuit.

The circuit/module for obtaining 624 may include circuitry and/orprogramming (e.g., code for obtaining 654 stored on the storage medium604) adapted to perform several functions relating to, for example,obtaining information as discussed herein (e.g., by retrieving theinformation from a memory device, by requesting the information fromanother component, etc.). In some aspects, the circuit/module forobtaining 624 (e.g., a means for obtaining) may correspond to, forexample, a processing circuit.

The circuit/module for determining that handover failed 628 may includecircuitry and/or programming (e.g., code for determining that handoverfailed 658 stored on the storage medium 604) adapted to perform severalfunctions relating to, for example, determining that handover a handoverwas not successful as discussed herein (e.g., based on receipt of ahandover failure message, a communication timeout, etc.). In someaspects, the circuit/module for determining that handover failed 628(e.g., a means for determining that handover failed) may correspond to,for example, a processing circuit.

The circuit/module for reverting 630 may include circuitry and/orprogramming (e.g., code for reverting 660 stored on the storage medium604) adapted to perform several functions relating to, for example,reverting to the use of prior context information as discussed herein(e.g., by retrieving the information from a memory device, in responseto a handover failure, etc.). In some aspects, the circuit/module forreverting 630 (e.g., a means for reverting) may correspond to, forexample, a processing circuit.

The circuit/module for using 632 may include circuitry and/orprogramming (e.g., code for using 662 stored on the storage medium 604)adapted to perform several functions relating to, for example, usingsecurity information as discussed herein (e.g., by retrieving theinformation from a memory device, verifying that a communication,connection, etc., is authorized, etc.). In some aspects, thecircuit/module for using 632 (e.g., a means for using) may correspondto, for example, a processing circuit.

The circuit/module for receiving 634 may include circuitry and/orprogramming (e.g., code for receiving 664 stored on the storage medium604) adapted to perform several functions relating to, for example,receiving information. In some scenarios, the circuit/module forreceiving 634 may obtain information (e.g., from the communicationinterface 602, the memory device, or some other component of theapparatus 600) and processes (e.g., decodes) the information. In somescenarios (e.g., if the circuit/module for receiving 634 is or includesan RF receiver), the circuit/module for receiving 634 may receiveinformation directly from a device that transmitted the information. Ineither case, the circuit/module for receiving 634 may output theobtained information to another component of the apparatus 600 (e.g.,the memory device 608, or some other component).

The circuit/module for receiving 634 (e.g., a means for receiving) maytake various forms. In some aspects, the circuit/module for receiving634 may correspond to, for example, an interface (e.g., a bus interface,a send/receive interface, or some other type of signal interface), acommunication device, a transceiver, a receiver, or some other similarcomponent as discussed herein. In some implementations, thecommunication interface 602 includes the circuit/module for receiving634 and/or the code for receiving 664. In some implementations, thecircuit/module for receiving 634 and/or the code for receiving 664 isconfigured to control the communication interface 602 (e.g., atransceiver or a receiver) to receive information.

The circuit/module for acquiring 636 may include circuitry and/orprogramming (e.g., code for acquiring 666 stored on the storage medium604) adapted to perform several functions relating to, for example,acquiring information as discussed herein (e.g., by conducting receivedsignal measurements, by retrieving the information from a memory device,by requesting the information from another component, etc.). In someaspects, the circuit/module for acquiring 636 (e.g., a means foracquiring) may correspond to, for example, a processing circuit.

The circuit/module for sending 638 may include circuitry and/orprogramming (e.g., code for sending 668 stored on the storage medium604) adapted to perform several functions relating to, for example,sending (e.g., transmitting) information. In some implementations, thecircuit/module for sending 638 may obtain information (e.g., from thecircuit/module for acquiring 636, the memory device 608, or some othercomponent of the apparatus 600), process the information (e.g., encodethe information for transmission), and send the information to anothercomponent (e.g., the transmitter 614, the communication interface 602,or some other component) that will transmit the information to anotherdevice. In some scenarios (e.g., if the circuit/module for sending 638includes a transmitter), the circuit/module for sending 638 transmitsthe information directly to another device (e.g., the ultimatedestination) via radio frequency signaling or some other type ofsignaling suitable for the applicable communication medium.

The circuit/module for sending 638 (e.g., a means for sending) may takevarious forms. In some aspects, the circuit/module for sending 638 maycorrespond to, for example, an interface (e.g., a bus interface, asend/receive interface, or some other type of signal interface), acommunication device, a transceiver, a transmitter, or some othersimilar component as discussed herein. In some implementations, thecommunication interface 602 includes the circuit/module for sending 638and/or the code for sending 668. In some implementations, thecircuit/module for sending 638 and/or the code for sending 668 isconfigured to control the communication interface 602 (e.g., atransceiver or a transmitter) to transmit information.

The circuit/module for determining that a source base station is asecondary base station 640 may include circuitry and/or programming(e.g., code for determining that a source base station is a secondarybase station 670 stored on the storage medium 604) adapted to performseveral functions relating to, for example, determining that a sourcebase station for SA mode is a secondary base station for NSA mode asdiscussed herein (e.g., based on which node will be the target SN,etc.). In some aspects, the circuit/module for determining that a sourcebase station is a secondary base station 640 (e.g., a means fordetermining that a source base station is a secondary base station) maycorrespond to, for example, a processing circuit.

The circuit/module for electing 642 may include circuitry and/orprogramming (e.g., code for electing 672 stored on the storage medium604) adapted to perform several functions relating to, for example,electing to not conduct a random access to a secondary base station asdiscussed herein (e.g., upon determining that a source base station forSA mode is a secondary base station for NSA mode, upon determining thatthe SN did not change, etc.). In some aspects, the circuit/module forelecting 642 (e.g., a means for electing) may correspond to, forexample, a processing circuit.

First Example Process

FIG. 7 illustrates a process 700 for communication in accordance withsome aspects of the disclosure. The process 700 may take place within aprocessing circuit (e.g., the processing circuit 610 of FIG. 6 ), whichmay be located in a UE, a gNB, a BS, an eNB, a CPE, or some othersuitable apparatus. Of course, in various aspects within the scope ofthe disclosure, the process 700 may be implemented by any suitableapparatus capable of supporting communication-related operations.

At block 702, an apparatus (e.g., a UE) operates in a standalone mode ofoperation with a first type of core network associated with a first typeof protocol stack. In some aspects, the first type of core network maybe a 3rd Generation Partnership Project (3GPP) 4G core network, i.e.,EPC (Evolved Packet Core), a 3GPP 5G core network, i.e., 5GC (5G Core),or another type of network or another type of network. In some aspects,the standalone mode of operation may involve connectivity with a 3rdGeneration Partnership Project (3GPP) New Radio (NR) network,connectivity with a 3GPP 5G core network, i.e., 5GC (5G Core), oranother type of connectivity.

In some implementations, the circuit/module for operating 620 of FIG. 6performs the operations of block 702 and/or other similar operations astaught herein. In some implementations, the code for operating 650 ofFIG. 6 is executed to perform the operations of block 702 and/or othersimilar operations as taught herein.

At block 704, the apparatus determines that the apparatus is to behanded-over from the standalone mode of operation to a non-standalonemode of operation. In some aspects, the determination that the apparatusis to be handed-over may include receiving a connection reconfigurationmessage including non-standalone mode configuration information for thesecond type of core network. In some aspects, the non-standalone mode ofoperation may involve dual connectivity with a 3GPP NR network (oranother type of network) and at least one other network.

In some implementations, the circuit/module for determining that a UE isto be handed-over 622 of FIG. 6 performs the operations of block 704and/or other similar operations as taught herein. In someimplementations, the code for determining that a UE is to be handed-over620 of FIG. 6 is executed to perform the operations of block 704 and/orother similar operations as taught herein.

At block 706, the apparatus operates in the non-standalone mode ofoperation with a second type of core network associated with a secondtype of protocol stack as a result of the determination. In someaspects, the second type of core network may be a 3rd GenerationPartnership Project (3GPP) 4G core network, i.e., EPC (Evolved PacketCore), a 3GPP 5G core network, i.e., 5GC (5G Core), or another type ofnetwork.

In some implementations, the circuit/module for operating 620 of FIG. 6performs the operations of block 706 and/or other similar operations astaught herein. In some implementations, the code for operating 650 ofFIG. 6 is executed to perform the operations of block 706 and/or othersimilar operations as taught herein.

In some aspects, a process in accordance with the teachings herein mayinclude any combination of the above operations.

First Optional Operations

FIG. 8 illustrates optional operations 800 for communication inaccordance with some aspects of the disclosure. In some aspects, theoperations 800 may be performed in conjunction with (e.g., as part of orin addition to) the process 700 of FIG. 7 . The operations 800 may takeplace within a processing circuit (e.g., the processing circuit 610 ofFIG. 6 ), which may be located in a UE, a gNB, a BS, an eNB, a CPE, orsome other suitable apparatus. Of course, in various aspects within thescope of the disclosure, the operations 800 may be implemented by anysuitable apparatus capable of supporting communication-relatedoperations.

At block 802, an apparatus (e.g., a UE) may obtain first contextinformation (e.g., protocol-related information or other context-relatedinformation) for the standalone mode of operation. In someimplementations, the circuit/module for obtaining 624 of FIG. 6 performsthe operations of block 802 and/or other similar operations as taughtherein. In some implementations, the code for obtaining 654 of FIG. 6 isexecuted to perform the operations of block 802 and/or other similaroperations as taught herein.

At block 804, the apparatus may obtain second context information forthe non-standalone mode of operation. In some implementations, thecircuit/module for obtaining 624 of FIG. 6 performs the operations ofblock 804 and/or other similar operations as taught herein. In someimplementations, the code for obtaining 654 of FIG. 6 is executed toperform the operations of block 804 and/or other similar operations astaught herein.

At block 806, the apparatus may maintain the first context informationand the second context information during handover from the standalonemode of operation to a non-standalone mode of operation. In someimplementations, the circuit/module for maintaining 626 of FIG. 6performs the operations of block 806 and/or other similar operations astaught herein. In some implementations, the code for maintaining 656 ofFIG. 6 is executed to perform the operations of block 806 and/or othersimilar operations as taught herein.

At block 808, the apparatus may determine that the handover failed. Insome implementations, the circuit/module for determining that handoverfailed 628 of FIG. 6 performs the operations of block 808 and/or othersimilar operations as taught herein. In some implementations, the codefor determining that handover failed 658 of FIG. 6 is executed toperform the operations of block 808 and/or other similar operations astaught herein.

At block 810, the apparatus may revert to use of the first contextinformation as a result of the determination that the handover failed.In some implementations, the circuit/module for reverting 630 of FIG. 6performs the operations of block 810 and/or other similar operations astaught herein. In some implementations, the code for reverting 660 ofFIG. 6 is executed to perform the operations of block 810 and/or othersimilar operations as taught herein.

At block 812, the apparatus may use first security information for thestandalone mode of operation. In some implementations, thecircuit/module for using 632 of FIG. 6 performs the operations of block812 and/or other similar operations as taught herein. In someimplementations, the code for using 662 of FIG. 6 is executed to performthe operations of block 812 and/or other similar operations as taughtherein.

At block 814, the apparatus may receive an indication to use the firstsecurity information for the non-standalone mode of operation. In someaspects, the indication may be received via an addition request message.In some implementations, the circuit/module for receiving 634 of FIG. 6performs the operations of block 814 and/or other similar operations astaught herein. In some implementations, the code for receiving 664 ofFIG. 6 is executed to perform the operations of block 814 and/or othersimilar operations as taught herein.

At block 816, the apparatus may use the first security information forthe non-standalone mode of operation as a result of receiving theindication. In some implementations, the circuit/module for using 632 ofFIG. 6 performs the operations of block 816 and/or other similaroperations as taught herein. In some implementations, the code for using662 of FIG. 6 is executed to perform the operations of block 816 and/orother similar operations as taught herein.

At block 818, the apparatus may acquire a first set of measurementinformation for at least one cell of a current serving Radio AccessTechnology (RAT). In some implementations, the circuit/module foracquiring 636 of FIG. 6 performs the operations of block 818 and/orother similar operations as taught herein. In some implementations, thecode for acquiring 666 of FIG. 6 is executed to perform the operationsof block 818 and/or other similar operations as taught herein.

At block 820, the apparatus may acquire a second set of measurementinformation for at least one other cell of a second type of RAT. In someimplementations, the circuit/module for acquiring 636 of FIG. 6 performsthe operations of block 820 and/or other similar operations as taughtherein. In some implementations, the code for acquiring 666 of FIG. 6 isexecuted to perform the operations of block 820 and/or other similaroperations as taught herein.

At block 822, the apparatus may send the first set of measurementinformation and the second set of measurement information to a servingcell while operating in the standalone mode of operation. In someimplementations, the circuit/module for sending 638 of FIG. 6 performsthe operations of block 822 and/or other similar operations as taughtherein. In some implementations, the code for sending 668 of FIG. 6 isexecuted to perform the operations of block 822 and/or other similaroperations as taught herein.

At block 824, the apparatus may send device capability bits indicatingwhether the apparatus supports: handover from SA to NSA, handover fromNSA to SA, inter-system handover from SA to NSA, inter-system handoverfrom NSA to SA, or any combination thereof. In some implementations, thecircuit/module for sending 638 of FIG. 6 performs the operations ofblock 824 and/or other similar operations as taught herein. In someimplementations, the code for sending 668 of FIG. 6 is executed toperform the operations of block 824 and/or other similar operations astaught herein.

At block 826, the apparatus may determine that a source base station forthe standalone mode of operation is a secondary base station for thenon-standalone mode of operation. In some implementations, thecircuit/module for determining that a source base station is a secondarybase station 640 of FIG. 6 performs the operations of block 826 and/orother similar operations as taught herein. In some implementations, thecode for determining that a source base station is a secondary basestation 670 of FIG. 6 is executed to perform the operations of block 826and/or other similar operations as taught herein.

At block 828, the apparatus may elect to not conduct a random access tothe secondary base station as a result of the determination at block 826that the source base station for the standalone mode of operation is thesecondary base station for the non-standalone mode of operation. In someimplementations, the circuit/module for electing 642 of FIG. 6 performsthe operations of block 828 and/or other similar operations as taughtherein. In some implementations, the code for electing 672 of FIG. 6 isexecuted to perform the operations of block 828 and/or other similaroperations as taught herein.

In some aspects, a process in accordance with the teachings herein mayinclude any combination of the above operations.

Second Example Apparatus

FIG. 9 illustrates a block diagram of an example hardware implementationof an apparatus 900 configured to communicate according to one or moreaspects of the disclosure. The apparatus 900 could embody or beimplemented within a gNB, a transmit receive point (TRP), a base station(BS), an eNode B (eNB), a CPE, or some other type of device thatsupports wireless communication. In various implementations, theapparatus 900 could embody or be implemented within an access terminal,an access point, or some other type of device. In variousimplementations, the apparatus 900 could embody or be implemented withina server, a personal computer, a mobile phone, a smart phone, a tablet,a portable computer, a sensor, an alarm, a vehicle, a machine, anentertainment device, a medical device, or any other electronic devicehaving circuitry.

The apparatus 900 includes a communication interface 902 (e.g., at leastone transceiver), a storage medium 904, a user interface 906, a memorydevice 908 (e.g., storing handover information 918), and a processingcircuit 910 (e.g., at least one processor). In various implementations,the user interface 906 may include one or more of: a keypad, a display,a speaker, a microphone, a touchscreen display, of some other circuitryfor receiving an input from or sending an output to a user. Thecommunication interface 902 may be coupled to one or more antennas 912,and may include a transmitter 914 and a receiver 916. In general, thecomponents of FIG. 9 may be similar to corresponding components of theapparatus 600 of FIG. 6 .

According to one or more aspects of the disclosure, the processingcircuit 910 may be adapted to perform any or all of the features,processes, functions, operations and/or routines for any or all of theapparatuses described herein. For example, the processing circuit 910may be configured to perform any of the steps, functions, and/orprocesses described with respect to FIGS. 1-5, 10, and 11 . As usedherein, the term “adapted” in relation to the processing circuit 910 mayrefer to the processing circuit 910 being one or more of configured,used, implemented, and/or programmed to perform a particular process,function, operation and/or routine according to various featuresdescribed herein.

The processing circuit 910 may be a specialized processor, such as anapplication specific integrated circuit (ASIC) that serves as a meansfor (e.g., structure for) carrying out any one of the operationsdescribed in conjunction with FIGS. 1-5, 10, and 11 . The processingcircuit 910 may serve as one example of a means for transmitting and/ora means for receiving. In some implementations, the processing circuit910 may provide and/or incorporate, at least in part, the functionalityof one or more of the system components described herein (e.g., themodule for SA/NSA handover 116 of FIG. 1 ).

According to at least one example of the apparatus 900, the processingcircuit 910 may include one or more of a circuit/module for determiningthat a UE is to be handed-over 920, a circuit/module for sending 922, acircuit/module for determining that communication uses a particular QoS924, a circuit/module for electing 926, a circuit/module for usingsecurity information 928, a circuit/module for using a data radio bearer930, a circuit/module for determining that a source base station is asecondary base station 932, or a circuit/module for receiving 934. Invarious implementations, the circuit/module for determining that a UE isto be handed-over 920, the circuit/module for sending 922, thecircuit/module for determining that communication uses a particular QoS924, the circuit/module for electing 926, a circuit/module for usingsecurity information 928, the circuit/module for using a data radiobearer 930, the circuit/module for determining that a source basestation is a secondary base station 932, or the circuit/module forreceiving 934 may provide and/or incorporate, at least in part, thefunctionality of one or more of the system components described herein(e.g., the module for SA/NSA handover 116 of FIG. 1 ).

As mentioned above, programming stored by the storage medium 904, whenexecuted by the processing circuit 910, causes the processing circuit910 to perform one or more of the various functions and/or processoperations described herein. For example, the programming may cause theprocessing circuit 910 to perform the various functions, steps, and/orprocesses described herein with respect to FIGS. 1-5, 10, and 11 invarious implementations. As shown in FIG. 9 , the storage medium 904 mayinclude one or more of code for determining that a UE is to behanded-over 940, code for sending 942, code for determining thatcommunication uses a particular QoS 944, code for electing 946, code forusing security information 948, code for using a data radio bearer 950,code for determining that a source base station is a secondary basestation 952, or code for receiving 954. In various implementations, thecode for determining that a UE is to be handed-over 940, the code forsending 942, the code for determining that communication uses aparticular QoS 944, the code for electing 946, the code for usingsecurity information 948, the code for using a data radio bearer 950,the code for determining that a source base station is a secondary basestation 952, or the code for receiving 954 may be executed or otherwiseused to provide the functionality described herein for thecircuit/module for determining that a UE is to be handed-over 920, thecircuit/module for sending 922, the circuit/module for determining thatcommunication uses a particular QoS 924, the circuit/module for electing926, a circuit/module for using security information 928, thecircuit/module for using a data radio bearer 930, the circuit/module fordetermining that a source base station is a secondary base station 932,or the circuit/module for receiving 934.

The circuit/module for determining that a UE is to be handed-over 920may include circuitry and/or programming (e.g., code for determiningthat a UE is to be handed-over 950 stored on the storage medium 904)adapted to perform several functions relating to, for example,determining that handover is indicated as discussed herein (e.g., basedon a handover trigger, etc.). In some aspects, the circuit/module fordetermining that a UE is to be handed-over 920 (e.g., a means fordetermining that a UE is to be handed-over) may correspond to, forexample, a processing circuit.

The circuit/module for sending 922 may include circuitry and/orprogramming (e.g., code for sending 942 stored on the storage medium904) adapted to perform several functions relating to, for example,sending (e.g., transmitting) information (e.g. a message, an indication,etc.). In some implementations, the circuit/module for sending 922 mayobtain information (e.g., from the memory device 908, or some othercomponent of the apparatus 900), process the information (e.g., encodethe information for transmission), and send the information to anothercomponent (e.g., the transmitter 914, the communication interface 902,or some other component) that will transmit the information to anotherdevice. In some scenarios (e.g., if the circuit/module for sending 922includes a transmitter), the circuit/module for sending 922 transmitsthe information directly to another device (e.g., the ultimatedestination) via radio frequency signaling or some other type ofsignaling suitable for the applicable communication medium.

The circuit/module for sending 922 (e.g., a means for sending) may takevarious forms. In some aspects, the circuit/module for sending 922 maycorrespond to, for example, an interface (e.g., a bus interface, asend/receive interface, or some other type of signal interface), acommunication device, a transceiver, a transmitter, or some othersimilar component as discussed herein. In some implementations, thecommunication interface 902 includes the circuit/module for sending 922and/or the code for sending 968. In some implementations, thecircuit/module for sending 922 and/or the code for sending 942 isconfigured to control the communication interface 902 (e.g., atransceiver or a transmitter) to transmit information.

The circuit/module for determining that communication uses a particularQoS 924 may include circuitry and/or programming (e.g., code fordetermining that communication uses a particular QoS 944 stored on thestorage medium 904) adapted to perform several functions relating to,for example, determining that communication by a UE uses a particularQoS as discussed herein (e.g., based on a received grant or otherscheduling information, based the requirements of an application, etc.).In some aspects, the circuit/module for determining that communicationuses a particular QoS 924 (e.g., a means for determining thatcommunication uses a particular QoS) may correspond to, for example, aprocessing circuit.

The circuit/module for electing 926 may include circuitry and/orprogramming (e.g., code for electing 946 stored on the storage medium904) adapted to perform several functions relating to, for example,electing to include measurement information in a message as discussedherein (e.g., upon determining that an SA/NSA handover or an NSA/SAhandover may be performed, etc.). In some aspects, the circuit/modulefor electing 926 (e.g., a means for electing) may correspond to, forexample, a processing circuit.

The circuit/module for using security information 928 may includecircuitry and/or programming (e.g., code for using security information948 stored on the storage medium 904) adapted to perform severalfunctions relating to, for example, using security information asdiscussed herein (e.g., by retrieving the information from a memorydevice, verifying that a communication, connection, etc., is authorized,etc.). In some aspects, the circuit/module for using securityinformation 928 (e.g., a means for using security information) maycorrespond to, for example, a processing circuit.

The circuit/module for using a data radio bearer 930 may includecircuitry and/or programming (e.g., code for using a data radio bearer950 stored on the storage medium 904) adapted to perform severalfunctions relating to, for example, using radio bearers as discussedherein (e.g., by causing information to be sent or received via ascheduled radio bearer, etc.). In some aspects, the circuit/module forusing a data radio bearer 930 (e.g., a means for using a data radiobearer) may correspond to, for example, a processing circuit.

The circuit/module for determining that a source base station is asecondary base station 932 may include circuitry and/or programming(e.g., code for determining that a source base station is a secondarybase station 952 stored on the storage medium 904) adapted to performseveral functions relating to, for example, determining that a sourcebase station for SA mode is a secondary base station for NSA mode asdiscussed herein (e.g., based on which node will be the target SN,etc.). In some aspects, the circuit/module for determining that a sourcebase station is a secondary base station 932 (e.g., a means fordetermining that a source base station is a secondary base station) maycorrespond to, for example, a processing circuit.

The circuit/module for receiving 934 may include circuitry and/orprogramming (e.g., code for receiving 954 stored on the storage medium904) adapted to perform several functions relating to, for example,receiving information. In some scenarios, the circuit/module forreceiving 934 may obtain information (e.g., from the communicationinterface 902, the memory device, or some other component of theapparatus 900) and processes (e.g., decodes) the information. In somescenarios (e.g., if the circuit/module for receiving 934 is or includesan RF receiver), the circuit/module for receiving 934 may receiveinformation directly from a device that transmitted the information. Ineither case, the circuit/module for receiving 934 may output theobtained information to another component of the apparatus 900 (e.g.,the memory device 908, or some other component).

The circuit/module for receiving 934 (e.g., a means for receiving) maytake various forms. In some aspects, the circuit/module for receiving934 may correspond to, for example, an interface (e.g., a bus interface,a send/receive interface, or some other type of signal interface), acommunication device, a transceiver, a receiver, or some other similarcomponent as discussed herein. In some implementations, thecommunication interface 902 includes the circuit/module for receiving934 and/or the code for receiving 954. In some implementations, thecircuit/module for receiving 934 and/or the code for receiving 954 isconfigured to control the communication interface 902 (e.g., atransceiver or a receiver) to receive information.

Second Example Process

FIG. 10 illustrates a process 1000 for communication in accordance withsome aspects of the disclosure. The process 1000 may take place within aprocessing circuit (e.g., the processing circuit 910 of FIG. 9 ), whichmay be located in a gNB, a BS, an eNB, a CPE, or some other suitableapparatus. Of course, in various aspects within the scope of thedisclosure, the process 1000 may be implemented by any suitableapparatus capable of supporting communication-related operations.

At block 1002, an apparatus (e.g., a base station) determines that auser equipment is to be handed-over from a standalone mode of operationto a non-standalone mode of operation.

In some implementations, the circuit/module for determining that a UE isto be handed-over 920 of FIG. 9 performs the operations of block 1002and/or other similar operations as taught herein. In someimplementations, the code for determining that a UE is to be handed-over940 of FIG. 9 is executed to perform the operations of block 1002 and/orother similar operations as taught herein.

At block 1004, the apparatus sends a message for handover of the userequipment from a first type of core network associated with a first typeof protocol stack to a second type of core network associated with asecond type of protocol stack as a result of the determination that theuser equipment is to be handed-over.

In some implementations, the circuit/module for sending 922 of FIG. 9performs the operations of block 1004 and/or other similar operations astaught herein. In some implementations, the code for sending 942 of FIG.9 is executed to perform the operations of block 1004 and/or othersimilar operations as taught herein.

In some aspects, a process in accordance with the teachings herein mayinclude any combination of the above operations.

Second Optional Operations

FIG. 11 illustrates optional operations 1100 for communication inaccordance with some aspects of the disclosure. In some aspects, theoperations 1100 may be performed in conjunction with (e.g., as part ofor in addition to) the process 1000 of FIG. 10 . The operations 1100 maytake place within a processing circuit (e.g., the processing circuit 910of FIG. 9 ), which may be located in a gNB, a BS, an eNB, a CPE, or someother suitable apparatus. Of course, in various aspects within the scopeof the disclosure, the operations 1100 may be implemented by anysuitable apparatus capable of supporting communication-relatedoperations.

At block 1102, an apparatus (e.g., a base station) may determine thatcommunication by the user equipment uses a particular quality ofservice. In some aspects, the particular quality of service may include(e.g., may be) a high performance quality of service.

In some implementations, the circuit/module for determining thatcommunication uses a particular QoS 924 of FIG. 9 performs theoperations of block 1102 and/or other similar operations as taughtherein. In some implementations, the code for determining thatcommunication uses a particular QoS 944 of FIG. 9 is executed to performthe operations of block 1102 and/or other similar operations as taughtherein.

At block 1104, the apparatus may elect to include in a message (e.g, themessage of block 1004) a first set of measurement information for atleast one cell connected to the first type of core network and a secondset of measurement information for at least one other cell connected tothe second type of core network. In some aspects, the election may bebased on the determination that the communication by the user equipmentuses a particular quality of service.

In some aspects, the message may include (e.g., may be) an indicationthat a serving base station for the standalone mode of operation is tobe a secondary base station for the non-standalone mode of operation. Insome aspects, the message may include (e.g., may be) a handover requiredmessage.

In some implementations, the circuit/module for electing 926 of FIG. 9performs the operations of block 1104 and/or other similar operations astaught herein. In some implementations, the code for electing 946 ofFIG. 9 is executed to perform the operations of block 1104 and/or othersimilar operations as taught herein.

At block 1106, the apparatus may use first security information for thestandalone mode of operation. In some implementations, thecircuit/module for using security information 928 of FIG. 9 performs theoperations of block 1106 and/or other similar operations as taughtherein. In some implementations, the code for using security information948 of FIG. 9 is executed to perform the operations of block 1106 and/orother similar operations as taught herein.

At block 1108, the apparatus may receive an indication to use the firstsecurity information for the non-standalone mode of operation. In someaspects, the indication may be received via an addition request message.In some implementations, the circuit/module for receiving 934 of FIG. 9performs the operations of block 1108 and/or other similar operations astaught herein. In some implementations, the code for receiving 954 ofFIG. 9 is executed to perform the operations of block 1108 and/or othersimilar operations as taught herein.

At block 1110, the apparatus may use the first security information forthe non-standalone mode of operation as a result of receiving theindication. In some implementations, the circuit/module for usingsecuring information 928 of FIG. 9 performs the operations of block 1110and/or other similar operations as taught herein. In someimplementations, the code for using security information 948 of FIG. 9is executed to perform the operations of block 1110 and/or other similaroperations as taught herein.

At block 1112, the apparatus may use at least one first data radiobearer for the standalone mode of operation. In some implementations,the circuit/module for using a data radio bearer 930 of FIG. 9 performsthe operations of block 1112 and/or other similar operations as taughtherein. In some implementations, the code for using a data radio bearer950 of FIG. 9 is executed to perform the operations of block 1112 and/orother similar operations as taught herein.

At block 1114, the apparatus may determine that a source base stationfor the standalone mode of operation is a secondary base station for thenon-standalone mode of operation. In some implementations, thecircuit/module for determining that a source base station is a secondarybase station 932 of FIG. 9 performs the operations of block 1114 and/orother similar operations as taught herein. In some implementations, thecode for determining that a source base station is a secondary basestation 952 of FIG. 9 is executed to perform the operations of block1114 and/or other similar operations as taught herein.

At block 1116, the apparatus may use the at least one first data radiobearer for the non-standalone mode of operation as a result of thedetermination at block 1114 that the source base station for thestandalone mode of operation is the secondary base station for thenon-standalone mode of operation. In some implementations, thecircuit/module for using a data radio bearer 930 of FIG. 9 performs theoperations of block 1116 and/or other similar operations as taughtherein. In some implementations, the code for using a data radio bearer950 of FIG. 9 is executed to perform the operations of block 1116 and/orother similar operations as taught herein.

At block 1118, the apparatus may receive configuration information via ahandover command instead of an addition request in response to thedetermination at block 1114 that the source base station for thestandalone mode of operation is the secondary base station for thenon-standalone mode of operation. In some implementations, thecircuit/module for receiving 934 of FIG. 9 performs the operations ofblock 1118 and/or other similar operations as taught herein. In someimplementations, the code for receiving 954 of FIG. 9 is executed toperform the operations of block 1118 and/or other similar operations astaught herein.

In some aspects, a process in accordance with the teachings herein mayinclude any combination of the above operations.

Third Example Apparatus

FIG. 12 illustrates a block diagram of an example hardwareimplementation of an apparatus 1200 configured to communicate accordingto one or more aspects of the disclosure. The apparatus 1200 couldembody or be implemented within a gNB, a transmit receive point (TRP), abase station (BS), an eNode B (eNB), a CPE, or some other type of devicethat supports wireless communication. In various implementations, theapparatus 1200 could embody or be implemented within an access terminal,an access point, or some other type of device. In variousimplementations, the apparatus 1200 could embody or be implementedwithin a server, a personal computer, a mobile phone, a smart phone, atablet, a portable computer, a sensor, an alarm, a vehicle, a machine,an entertainment device, a medical device, or any other electronicdevice having circuitry.

The apparatus 1200 includes a communication interface 1202 (e.g., atleast one transceiver), a storage medium 1204, a user interface 1206, amemory device 1208 (e.g., storing handover information 1218), and aprocessing circuit 1210 (e.g., at least one processor). In variousimplementations, the user interface 1206 may include one or more of: akeypad, a display, a speaker, a microphone, a touchscreen display, ofsome other circuitry for receiving an input from or sending an output toa user. The communication interface 1202 may be coupled to one or moreantennas 1212, and may include a transmitter 1214 and a receiver 1216.In general, the components of FIG. 12 may be similar to correspondingcomponents of the apparatus 600 of FIG. 6 .

According to one or more aspects of the disclosure, the processingcircuit 1210 may be adapted to perform any or all of the features,processes, functions, operations and/or routines for any or all of theapparatuses described herein. For example, the processing circuit 1210may be configured to perform any of the steps, functions, and/orprocesses described with respect to FIGS. 1-5 and 13 . As used herein,the term “adapted” in relation to the processing circuit 1210 may referto the processing circuit 1210 being one or more of configured, used,implemented, and/or programmed to perform a particular process,function, operation and/or routine according to various featuresdescribed herein (e.g., the module for SA/NSA handover 116 of FIG. 1 ).

The processing circuit 1210 may be a specialized processor, such as anapplication specific integrated circuit (ASIC) that serves as a meansfor (e.g., structure for) carrying out any one of the operationsdescribed in conjunction with FIGS. 1-5 and 13 . The processing circuit1210 may serve as one example of a means for transmitting and/or a meansfor receiving. In some implementations, the processing circuit 1210 mayprovide and/or incorporate, at least in part, the functionality of oneor more of the system components described herein (e.g., the module forSA/NSA handover 116 of FIG. 1 ).

According to at least one example of the apparatus 1200, the processingcircuit 1210 may include one or more of a circuit/module for determining1220, a circuit/module for sending 1222, a circuit/module for electing1224, a circuit/module for selecting 1226, or a circuit/module forreceiving 1228. In various implementations, the circuit/module fordetermining 1220, the circuit/module for sending 1222, thecircuit/module for electing 1224, the circuit/module for selecting 1226,or the circuit/module for receiving 1228 may provide and/or incorporate,at least in part, the functionality of one or more of the systemcomponents described herein.

As mentioned above, programming stored by the storage medium 1204, whenexecuted by the processing circuit 1210, causes the processing circuit1210 to perform one or more of the various functions and/or processoperations described herein. For example, the programming may cause theprocessing circuit 1210 to perform the various functions, steps, and/orprocesses described herein with respect to FIGS. 1-5 and 13 in variousimplementations. As shown in FIG. 12 , the storage medium 1204 mayinclude one or more of code for determining 1240, code for sending 1242,code for electing 1244, code for selecting 1246, or code for receiving1248. In various implementations, the code for determining 1240, thecode for sending 1242, the code for electing 1244, the code forselecting 1246, or the code for receiving 1248 may be executed orotherwise used to provide the functionality described herein for thecircuit/module for determining 1220, the circuit/module for sending1222, the circuit/module for electing 1224, the circuit/module forselecting 1226, or the circuit/module for receiving 1228.

The circuit/module for determining 1220 may include circuitry and/orprogramming (e.g., code for determining 1240 stored on the storagemedium 1204) adapted to perform several functions relating to, forexample, determining that handover is indicated as discussed herein(e.g., based on a handover trigger, etc.). In some aspects, thecircuit/module for determining 1220 (e.g., a means for determining) maycorrespond to, for example, a processing circuit.

The circuit/module for sending 1222 may include circuitry and/orprogramming (e.g., code for sending 1242 stored on the storage medium1204) adapted to perform several functions relating to, for example,sending (e.g., transmitting) information (e.g. a message, an indication,etc.). In some implementations, the circuit/module for sending 1222 mayobtain information (e.g., from the memory device 1208, or some othercomponent of the apparatus 1200), process the information (e.g., encodethe information for transmission), and send the information to anothercomponent (e.g., the transmitter 1214, the communication interface 1202,or some other component) that will transmit the information to anotherdevice. In some scenarios (e.g., if the circuit/module for sending 1222includes a transmitter), the circuit/module for sending 1222 transmitsthe information directly to another device (e.g., the ultimatedestination) via radio frequency signaling or some other type ofsignaling suitable for the applicable communication medium.

The circuit/module for sending 1222 (e.g., a means for sending) may takevarious forms. In some aspects, the circuit/module for sending 1222 maycorrespond to, for example, an interface (e.g., a bus interface, asend/receive interface, or some other type of signal interface), acommunication device, a transceiver, a transmitter, or some othersimilar component as discussed herein. In some implementations, thecommunication interface 1202 includes the circuit/module for sending1222 and/or the code for sending 1242. In some implementations, thecircuit/module for sending 1222 and/or the code for sending 1242 isconfigured to control the communication interface 1202 (e.g., atransceiver or a transmitter) to transmit information.

The circuit/module for electing 1224 may include circuitry and/orprogramming (e.g., code for electing 1244 stored on the storage medium1204) adapted to perform several functions relating to, for example,electing to send configuration information to a serving base station asdiscussed herein (e.g., upon selecting a serving base station for SA asa secondary base station for NSA, etc.). In some aspects, thecircuit/module for electing 1224 (e.g., a means for electing) maycorrespond to, for example, a processing circuit.

The circuit/module for selecting 1226 may include circuitry and/orprogramming (e.g., code for selecting 1246 stored on the storage medium1204) adapted to perform several functions relating to, for example,selecting a serving base station for SA as a secondary base station forNSA as discussed herein (e.g., upon determining that the serving basestation provides better QoS for a particular communication, etc.). Insome aspects, the circuit/module for selecting 1226 (e.g., a means forselecting) may correspond to, for example, a processing circuit.

The circuit/module for receiving 1228 may include circuitry and/orprogramming (e.g., code for receiving 1248 stored on the storage medium1204) adapted to perform several functions relating to, for example,receiving information. In some scenarios, the circuit/module forreceiving 1228 may obtain information (e.g., from the communicationinterface 1202, the memory device, or some other component of theapparatus 1200) and processes (e.g., decodes) the information. In somescenarios (e.g., if the circuit/module for receiving 1228 is or includesan RF receiver), the circuit/module for receiving 1228 may receiveinformation directly from a device that transmitted the information. Ineither case, the circuit/module for receiving 1228 may output theobtained information to another component of the apparatus 1200 (e.g.,the memory device 1208, or some other component).

The circuit/module for receiving 1228 (e.g., a means for receiving) maytake various forms. In some aspects, the circuit/module for receiving1228 may correspond to, for example, an interface (e.g., a businterface, a send/receive interface, or some other type of signalinterface), a communication device, a transceiver, a receiver, or someother similar component as discussed herein. In some implementations,the communication interface 1202 includes the circuit/module forreceiving 1228 and/or the code for receiving 1248. In someimplementations, the circuit/module for receiving 1228 and/or the codefor receiving 1248 is configured to control the communication interface1202 (e.g., a transceiver or a receiver) to receive information.

Third Example Process

FIG. 13 illustrates a process 1300 for communication in accordance withsome aspects of the disclosure. The process 1300 may take place within aprocessing circuit (e.g., the processing circuit 1210 of FIG. 12 ),which may be located in a gNB, a BS, an eNB, a CPE, or some othersuitable apparatus. Of course, in various aspects within the scope ofthe disclosure, the process 1300 may be implemented by any suitableapparatus capable of supporting communication-related operations.

At block 1302, an apparatus (e.g., a base station) determine that a userequipment is to be handed-over from a standalone mode of operation to anon-standalone mode of operation. In some aspects, the determination maybe based on: a quality of service associated with the user equipment,multi-network capability of the user equipment, at least one measurementreport from the user equipment, at least one policy, or any combinationthereof.

In some implementations, the circuit/module for determining 1220 of FIG.12 performs the operations of block 1302 and/or other similar operationsas taught herein. In some implementations, the code for determining 1240of FIG. 12 is executed to perform the operations of block 1302 and/orother similar operations as taught herein.

At block 1304, the apparatus sends a message for handover of the userequipment from a first type of core network associated with a first typeof protocol stack to a second type of core network associated with asecond type of protocol stack as a result of the determination that theuser equipment is to be handed-over. In some aspects, the message mayinclude (e.g., may be) an addition request message.

In some implementations, the circuit/module for sending 1222 of FIG. 12performs the operations of block 1304 and/or other similar operations astaught herein. In some implementations, the code for sending 1242 ofFIG. 12 is executed to perform the operations of block 1304 and/or othersimilar operations as taught herein.

In some cases, the process 1300 may include the operations of optionalblock 1306 that involve selecting a serving base station for thestandalone mode of operation as a secondary base station for thenon-standalone mode of operation. In some aspects, the selection may bebased on at least one measurement report from the user equipment. Insome aspects, the at least one measurement report may include (e.g., maybe): a first set of measurement information for at least one cellconnected to the first type of core network; and a second set ofmeasurement information for at least one other cell connected to thesecond type of core network. In some aspects, the selection may be basedon an indication that the serving base station for the standalone modeof operation is to be the secondary base station for the non-standalonemode of operation. In some aspects, the indication may be received via ahandover request message. In some aspects, the message may include(e.g., may be) an indication that the serving base station is to use,for the non-standalone mode of operation, at least one data radio bearerthat was used for the standalone mode of operation. In some aspects, themessage may include (e.g., may be) an indication that the serving basestation is to use, for the non-standalone mode of operation, securityinformation that was used for the standalone mode of operation. In someaspects, the message may include (e.g., may be) a handover requestacknowledgement message. In some aspects, the message may include (e.g.,may be) an addition request message.

In some implementations, the circuit/module for selecting 1226 of FIG.12 performs the operations of block 1306 and/or other similar operationsas taught herein. In some implementations, the code for selecting 1246of FIG. 12 is executed to perform the operations of block 1306 and/orother similar operations as taught herein.

In some cases, the process 1300 may include the operations of optionalblock 1308 that involve electing to send configuration information tothe serving base station via a handover request acknowledgment messageinstead of an addition request message as a result of the selection.

In some implementations, the circuit/module for electing 1224 of FIG. 12performs the operations of block 1308 and/or other similar operations astaught herein. In some implementations, the code for electing 1244 ofFIG. 12 is executed to perform the operations of block 1308 and/or othersimilar operations as taught herein.

In some aspects, a process in accordance with the teachings herein mayinclude any combination of the above operations.

Fourth Example Apparatus

FIG. 14 illustrates a block diagram of an example hardwareimplementation of an apparatus 1400 configured to communicate accordingto one or more aspects of the disclosure. The apparatus 1400 couldembody or be implemented within a UE, a gNB, a transmit receive point(TRP), a base station (BS), an eNode B (eNB), a CPE, or some other typeof device that supports wireless communication. In variousimplementations, the apparatus 1400 could embody or be implementedwithin an access terminal, an access point, or some other type ofdevice. In various implementations, the apparatus 1400 could embody orbe implemented within a server, a personal computer, a mobile phone, asmart phone, a tablet, a portable computer, a sensor, an alarm, avehicle, a machine, an entertainment device, a medical device, or anyother electronic device having circuitry.

The apparatus 1400 includes a communication interface 1402 (e.g., atleast one transceiver), a storage medium 1404, a user interface 1406, amemory device 1408 (e.g., storing handover information 1418), and aprocessing circuit 1410 (e.g., at least one processor). In variousimplementations, the user interface 1406 may include one or more of: akeypad, a display, a speaker, a microphone, a touchscreen display, ofsome other circuitry for receiving an input from or sending an output toa user. The communication interface 1402 may be coupled to one or moreantennas 1412, and may include a transmitter 1414 and a receiver 1416.In general, the components of FIG. 14 may be similar to correspondingcomponents of the apparatus 600 of FIG. 6 .

According to one or more aspects of the disclosure, the processingcircuit 1410 may be adapted to perform any or all of the features,processes, functions, operations and/or routines for any or all of theapparatuses described herein. For example, the processing circuit 1410may be configured to perform any of the steps, functions, and/orprocesses described with respect to FIGS. 1-5 and 15 . As used herein,the term “adapted” in relation to the processing circuit 1410 may referto the processing circuit 1410 being one or more of configured, used,implemented, and/or programmed to perform a particular process,function, operation and/or routine according to various featuresdescribed herein.

The processing circuit 1410 may be a specialized processor, such as anapplication specific integrated circuit (ASIC) that serves as a meansfor (e.g., structure for) carrying out any one of the operationsdescribed in conjunction with FIGS. 1-5 and 15 . The processing circuit1410 may serve as one example of a means for transmitting and/or a meansfor receiving. In some implementations, the processing circuit 1410 mayprovide and/or incorporate, at least in part, the functionality of oneor more of the system components described herein (e.g., the module forSA/NSA handover 116 of FIG. 1 ).

According to at least one example of the apparatus 1400, the processingcircuit 1410 may include one or more of a circuit/module forcommunicating 1420, a circuit/module for handover 1422, a circuit/modulefor receiving 1424, a circuit/module for determining 1426, or acircuit/module for sending 1428. In various implementations, thecircuit/module for communicating 1420, the circuit/module for handover1422, the circuit/module for receiving 1424, the circuit/module fordetermining 1426, or the circuit/module for sending 1428 may provideand/or incorporate, at least in part, the functionality of one or moreof the system components described herein (e.g., the module for SA/NSAhandover 116 of FIG. 1 ).

As mentioned above, programming stored by the storage medium 1404, whenexecuted by the processing circuit 1410, causes the processing circuit1410 to perform one or more of the various functions and/or processoperations described herein. For example, the programming may cause theprocessing circuit 1410 to perform the various functions, steps, and/orprocesses described herein with respect to FIGS. 1-5 and 15 in variousimplementations. As shown in FIG. 14 , the storage medium 1404 mayinclude one or more of code for communicating 1440, code for handover1442, code for receiving 1444, code for determining 1446, or code forsending 1448. In various implementations, the code for communicating1440, the code for handover 1442, the code for receiving 1444, the codefor determining 1446, or the code for sending 1448 may be executed orotherwise used to provide the functionality described herein for thecircuit/module for communicating 1420, the circuit/module for handover1422, the circuit/module for receiving 1424, the circuit/module fordetermining 1426, or the circuit/module for sending 1428.

The circuit/module for communicating 1420 may include circuitry and/orprogramming (e.g., code for communicating 1440 stored on the storagemedium 1404) adapted to perform several functions relating to, forexample, communicating information. In some implementations, thecommunication involves receiving the information. In someimplementations, the communication involves sending (e.g., transmitting)the information.

The information may take different forms in different scenarios. In someaspects, the circuit/module for communicating 1420 may communicate amessage. In some aspects, the circuit/module for communicating 1424 maycommunicate an indication.

In some implementations where the communicating involves receivinginformation, the circuit/module for communicating 1420 receivesinformation (e.g., from the communication interface 1402, the receiver1416, the memory device 1408, some other component of the apparatus1400, or some other device), processes (e.g., decodes) the information,and outputs the information to another component of the apparatus 1400(e.g., the memory device 1408 or some other component). In somescenarios (e.g., if the circuit/module for communicating 1420 includes areceiver), the communicating involves the circuit/module forcommunicating 1420 receiving information directly from a device thattransmitted the information (e.g., via radio frequency signaling or someother type of signaling suitable for the applicable communicationmedium).

In some implementations where the communicating involves sendinginformation, the circuit/module for communicating 1420 obtainsinformation (e.g., from the memory device 1408 or some other componentof the apparatus 1400), processes (e.g., encodes) the information, andoutputs the processed information. In some scenarios, the communicatinginvolves sending the information to another component of the apparatus1400 (e.g., the transmitter 1414, the communication interface 1402, orsome other component) that will transmit the information to anotherdevice. In some scenarios (e.g., if the circuit/module for communicating1420 includes a transmitter), the communicating involves thecircuit/module for communicating 1420 transmitting the informationdirectly to another device (e.g., the ultimate destination) via radiofrequency signaling or some other type of signaling suitable for theapplicable communication medium.

The circuit/module for communicating 1420 (e.g., a means forcommunicating) may take various forms. In some aspects, thecircuit/module for communicating 1424 may correspond to, for example, aninterface (e.g., a bus interface, a send/receive interface, or someother type of signal interface), a communication device, a transceiver,a transmitter, a receiver, or some other similar component as discussedherein. In some implementations, the communication interface 1402includes the circuit/module for communicating 1420 and/or the code forcommunicating 1440. In some implementations, the circuit/module forcommunicating 1420 and/or the code for communicating 1440 is configuredto control the communication interface 1402 (e.g., a transceiver, areceiver, or a transmitter) to communicate the information.

The circuit/module for handover 1422 may include circuitry and/orprogramming (e.g., code for handover 1442 stored on the storage medium1204) adapted to perform several functions relating to, for example,handing over a UE from a first type of core network to a second type ofcore network as discussed herein (e.g., upon determining that the secondcore network provides a service that the first core network does notprovide, etc.). In some aspects, the circuit/module for handover 1422(e.g., a means for handover) may correspond to, for example, aprocessing circuit.

The circuit/module for receiving 1424 may include circuitry and/orprogramming (e.g., code for receiving 1444 stored on the storage medium1404) adapted to perform several functions relating to, for example,receiving information. In some scenarios, the circuit/module forreceiving 1424 may obtain information (e.g., from the communicationinterface 1402, the memory device, or some other component of theapparatus 1400) and processes (e.g., decodes) the information. In somescenarios (e.g., if the circuit/module for receiving 1424 is or includesan RF receiver), the circuit/module for receiving 1424 may receiveinformation directly from a device that transmitted the information. Ineither case, the circuit/module for receiving 1424 may output theobtained information to another component of the apparatus 1400 (e.g.,the memory device 1408, or some other component).

The circuit/module for receiving 1424 (e.g., a means for receiving) maytake various forms. In some aspects, the circuit/module for receiving1424 may correspond to, for example, an interface (e.g., a businterface, a send/receive interface, or some other type of signalinterface), a communication device, a transceiver, a receiver, or someother similar component as discussed herein. In some implementations,the communication interface 1402 includes the circuit/module forreceiving 1424 and/or the code for receiving 1444. In someimplementations, the circuit/module for receiving 1424 and/or the codefor receiving 1444 is configured to control the communication interface1402 (e.g., a transceiver or a receiver) to receive information.

The circuit/module for determining 1426 may include circuitry and/orprogramming (e.g., code for determining 1446 stored on the storagemedium 1404) adapted to perform several functions relating to, forexample, determining information or a condition as discussed herein. Insome aspects, the circuit/module for determining 1426 (e.g., a means fordetermining) may correspond to, for example, a processing circuit.

The circuit/module for sending 1428 may include circuitry and/orprogramming (e.g., code for sending 1448 stored on the storage medium1404) adapted to perform several functions relating to, for example,sending (e.g., transmitting) information (e.g. a message, an indication,etc.). In some implementations, the circuit/module for sending 1428 mayobtain information (e.g., from the memory device 1408, or some othercomponent of the apparatus 1400), process the information (e.g., encodethe information for transmission), and send the information to anothercomponent (e.g., the transmitter 1414, the communication interface 1402,or some other component) that will transmit the information to anotherdevice. In some scenarios (e.g., if the circuit/module for sending 1428includes a transmitter), the circuit/module for sending 1428 transmitsthe information directly to another device (e.g., the ultimatedestination) via radio frequency signaling or some other type ofsignaling suitable for the applicable communication medium.

The circuit/module for sending 1428 (e.g., a means for sending) may takevarious forms. In some aspects, the circuit/module for sending 1428 maycorrespond to, for example, an interface (e.g., a bus interface, asend/receive interface, or some other type of signal interface), acommunication device, a transceiver, a transmitter, or some othersimilar component as discussed herein. In some implementations, thecommunication interface 1402 includes the circuit/module for sending1428 and/or the code for sending 1448. In some implementations, thecircuit/module for sending 1428 and/or the code for sending 1448 isconfigured to control the communication interface 1402 (e.g., atransceiver or a transmitter) to transmit information.

Fourth Example Process

FIG. 15 illustrates a process 1500 for communication in accordance withsome aspects of the disclosure. The process 1500 may take place within aprocessing circuit (e.g., the processing circuit 1410 of FIG. 14 ),which may be located in a UE, a gNB, a BS, an eNB, a CPE, or some othersuitable apparatus. Of course, in various aspects within the scope ofthe disclosure, the process 1500 may be implemented by any suitableapparatus capable of supporting communication-related operations.

At block 1502, an apparatus (e.g., a base station) communicates amessage for a handover of a user equipment between a standalone mode ofoperation and a non-standalone mode of operation. In some aspects, themessage may be a handover request message.

In some implementations, the circuit/module for communicating 1420 ofFIG. 14 performs the operations of block 1502 and/or other similaroperations as taught herein. In some implementations, the code forcommunicating 1440 of FIG. 14 is executed to perform the operations ofblock 1502 and/or other similar operations as taught herein.

At block 1504, the apparatus hands-over the user equipment from a firsttype of core network associated with a first type of protocol stack to asecond type of core network associated with a second type of protocolstack as a result of communicating the message.

The handover may take different forms in different scenarios. In someaspects, the handover may be from the standalone mode of operation tothe non-standalone mode of operation. In some aspects, the handover maybe from the non-standalone mode of operation to the standalone mode ofoperation.

In some implementations, the circuit/module for handover 1422 of FIG. 14performs the operations of block 1504 and/or other similar operations astaught herein. In some implementations, the code for handover 1442 ofFIG. 14 is executed to perform the operations of block 1504 and/or othersimilar operations as taught herein.

In some aspects, the standalone mode of operation may include (e.g., maybe) connectivity with a 3rd Generation Partnership Project (3GPP) NewRadio (NR) network. In some aspects, the non-standalone mode ofoperation may include (e.g., may be) dual connectivity with a 3GPP NRnetwork and at least one other network.

In some aspects, the first type of core network may include (e.g., maybe) a 3rd Generation Partnership Project (3GPP) Long Term Evolution(LTE) core network. In some aspects, the second type of core network mayinclude (e.g., may be) a 3GPP New Radio (NR) core network.

In some aspects, the message may include (e.g., may be) a handoverrequired message. In this case, the communicating of the message mayinclude sending the handover required message.

In some aspects, the message may include (e.g., may be) a connectionreconfiguration message. In this case, the communicating of the messagemay include receiving the connection reconfiguration message.

In some aspects, a process in accordance with the teachings herein mayinclude any combination of the above operations.

Other Aspects

Any of the following aspects may be implemented independently and/orcombined with other aspects or embodiments disclosed herein.

In a first aspect, the disclosure may provide an apparatus configuredfor communication that includes a processing circuit and an interfacecoupled to the processing circuit. The processing circuit may beconfigured to: operate in a standalone mode of operation with a firsttype of core network associated with a first type of protocol stack;determine that the apparatus is to be handed-over from the standalonemode of operation to a non-standalone mode of operation; and operate ina non-standalone mode of operation with a second type of core networkassociated with a second type of protocol stack as a result of thedetermination.

In the first aspect, the disclosure may provide a method ofcommunication for an apparatus. The method may include: operating in astandalone mode of operation with a first type of core networkassociated with a first type of protocol stack; determining that theapparatus is to be handed-over from the standalone mode of operation toa non-standalone mode of operation; and operating in a non-standalonemode of operation with a second type of core network associated with asecond type of protocol stack as a result of the determination.

In the first aspect, the disclosure may provide an apparatus configuredfor communication. The apparatus may include: means for operating in astandalone mode of operation with a first type of core networkassociated with a first type of protocol stack; means for determiningthat the apparatus is to be handed-over from the standalone mode ofoperation to a non-standalone mode of operation; and means for operatingin a non-standalone mode of operation with a second type of core networkassociated with a second type of protocol stack as a result of thedetermination.

In the first aspect, the disclosure may provide a non-transitorycomputer-readable medium storing computer-executable code, includingcode to: operate in a standalone mode of operation with a first type ofcore network associated with a first type of protocol stack; determinethat the apparatus is to be handed-over from the standalone mode ofoperation to a non-standalone mode of operation; and operate in anon-standalone mode of operation with a second type of core networkassociated with a second type of protocol stack as a result of thedetermination.

The first aspect may be modified based on one or more of the following.The first aspect may include obtaining first context information for thestandalone mode of operation; obtaining second context information forthe non-standalone mode of operation; and maintaining the first contextinformation and the second context information during handover from thestandalone mode of operation to a non-standalone mode of operation. Thefirst aspect may include determining that the handover failed; andreverting to use of the first context information as a result of thedetermination that the handover failed. The first aspect may involve thedetermination that the apparatus is to be handed-over includingreceiving a connection reconfiguration message including non-standalonemode configuration information for the second type of core network. Thefirst aspect may include using first security information for thestandalone mode of operation; receiving an indication to use the firstsecurity information for the non-standalone mode of operation; and usingthe first security information for the standalone mode of operation as aresult of receiving the indication. The first aspect may involve theindication being received via an addition request message. The firstaspect may include acquiring a first set of measurement information forat least one cell of a current serving RAT (Radio Access Technology);acquiring a second set of measurement information for at least one othercell of a second type of RAT; and sending the first set of measurementinformation and the second set of measurement information to a servingcell while operating in the standalone mode of operation. The firstaspect may involve the standalone mode of operation includingconnectivity with a 3rd Generation Partnership Project (3GPP) New Radio(NR) network; and the non-standalone mode of operation including dualconnectivity with a 3GPP NR network and at least one other network. Thefirst aspect may involve the first type of core network including a 3rdGeneration Partnership Project (3GPP) 4G core network; and the secondtype of core network including a 3GPP 5G core network. The first aspectmay include sending device capability bits indicating whether theapparatus supports: handover from SA to NSA, handover from NSA to SA,inter-system handover from SA to NSA, inter-system handover from NSA toSA, or any combination thereof. The first aspect may include determiningthat a source base station for the standalone mode of operation is asecondary base station for the non-standalone mode of operation; andelecting to not conduct a random access to the secondary base station asa result of the determination that the source base station for thestandalone mode of operation is the secondary base station for thenon-standalone mode of operation.

In a second aspect, the disclosure may provide an apparatus configuredfor communication that includes a processing circuit and an interfacecoupled to the processing circuit. The processing circuit may beconfigured to: determine that a user equipment is to be handed-over froma standalone mode of operation to a non-standalone mode of operation;and send a message for handover of the user equipment from a first typeof core network associated with a first type of protocol stack to asecond type of core network associated with a second type of protocolstack as a result of the determination that the user equipment is to behanded-over.

In the second aspect, the disclosure may provide a method ofcommunication for an apparatus. The method may include: determining thata user equipment is to be handed-over from a standalone mode ofoperation to a non-standalone mode of operation; and sending a messagefor handover of the user equipment from a first type of core networkassociated with a first type of protocol stack to a second type of corenetwork associated with a second type of protocol stack as a result ofthe determination that the user equipment is to be handed-over.

In the second aspect, the disclosure may provide an apparatus configuredfor communication. The apparatus may include: means for determining thata user equipment is to be handed-over from a standalone mode ofoperation to a non-standalone mode of operation; and means for sending amessage for handover of the user equipment from a first type of corenetwork associated with a first type of protocol stack to a second typeof core network associated with a second type of protocol stack as aresult of the determination that the user equipment is to behanded-over.

In the second aspect, the disclosure may provide a non-transitorycomputer-readable medium storing computer-executable code, includingcode to: determine that a user equipment is to be handed-over from astandalone mode of operation to a non-standalone mode of operation; andsend a message for handover of the user equipment from a first type ofcore network associated with a first type of protocol stack to a secondtype of core network associated with a second type of protocol stack asa result of the determination that the user equipment is to behanded-over.

The second aspect may be modified based on one or more of the following.The second aspect may involve the determination that the user equipmentis to be handed-over including: determining that the standalone mode ofoperation does not provide a particular type of service. The secondaspect may involve the particular type of service including Voice overNew Radio (VoNR) service. The second aspect may involve the messageincluding: a first set of measurement information for at least one cellconnected to the first type of core network; and a second set ofmeasurement information for at least one other cell connected to thesecond type of core network. The second aspect may involve: the firstset of measurement information including 3rd Generation PartnershipProject (3GPP) Evolved Universal Terrestrial Radio Access (E-UTRA)measurement information; and the second set of measurement informationincluding 3GPP New Radio (NR) measurement information. The second aspectmay include: determining that communication by the user equipment uses aparticular quality of service; and electing to include in the message afirst set of measurement information for at least one cell connected tothe first type of core network and a second set of measurementinformation for at least one other cell connected to the second type ofcore network, wherein the election is based on the determination thatthe communication by the user equipment uses a particular quality ofservice. The second aspect may involve the particular quality of serviceincluding a high performance quality of service. The second aspect mayinvolve the message including an indication that a serving base stationfor the standalone mode of operation is to be a secondary base stationfor the non-standalone mode of operation. The second aspect may involvethe message including a handover required message. The second aspect mayinclude: using first security information for the standalone mode ofoperation; receiving an indication to use the first security informationfor the non-standalone mode of operation; and using the first securityinformation for the standalone mode of operation as a result ofreceiving the indication. The second aspect may involve the indicationbeing received via an addition request message. The second aspect mayinclude: using at least one first data radio bearer for the standalonemode of operation; determining that a source base station for thestandalone mode of operation is a secondary base station for thenon-standalone mode of operation; and using the at least one first dataradio bearer for the non-standalone mode of operation as a result of thedetermination that the source base station for the standalone mode ofoperation is the secondary base station for the non-standalone mode ofoperation. The second aspect may include: determining that a source basestation for the standalone mode of operation is a secondary base stationfor the non-standalone mode of operation; and receiving configurationinformation via a handover command instead of an addition request inresponse to the determination that the source base station for thestandalone mode of operation is the secondary base station for thenon-standalone mode of operation.

In a third aspect, the disclosure may provide an apparatus configuredfor communication that includes a processing circuit and an interfacecoupled to the processing circuit. The processing circuit may beconfigured to: determine that a user equipment is to be handed-over froma standalone mode of operation to a non-standalone mode of operation;and send a message for handover of the user equipment from a first typeof core network associated with a first type of protocol stack to asecond type of core network associated with a second type of protocolstack as a result of the determination that the user equipment is to behanded-over.

In the third aspect, the disclosure may provide a method ofcommunication for an apparatus. The method may include: determining thata user equipment is to be handed-over from a standalone mode ofoperation to a non-standalone mode of operation; and sending a messagefor handover of the user equipment from a first type of core networkassociated with a first type of protocol stack to a second type of corenetwork associated with a second type of protocol stack as a result ofthe determination that the user equipment is to be handed-over.

In the third aspect, the disclosure may provide an apparatus configuredfor communication. The apparatus may include: means for determining thata user equipment is to be handed-over from a standalone mode ofoperation to a non-standalone mode of operation; and means for sending amessage for handover of the user equipment from a first type of corenetwork associated with a first type of protocol stack to a second typeof core network associated with a second type of protocol stack as aresult of the determination that the user equipment is to behanded-over.

In the third aspect, the disclosure may provide a non-transitorycomputer-readable medium storing computer-executable code, includingcode to: determine that a user equipment is to be handed-over from astandalone mode of operation to a non-standalone mode of operation; andsend a message for handover of the user equipment from a first type ofcore network associated with a first type of protocol stack to a secondtype of core network associated with a second type of protocol stack asa result of the determination that the user equipment is to behanded-over.

The third aspect may be modified based on one or more of the following.The third aspect may involve the determination being based on: a qualityof service associated with the user equipment, multi-network capabilityof the user equipment, at least one measurement report from the userequipment, at least one policy, or any combination thereof. The thirdaspect may involve the message including an addition request message.The third aspect may include selecting a serving base station for thestandalone mode of operation as a secondary base station for thenon-standalone mode of operation. The third aspect may involve theselection being based on at least one measurement report from the userequipment. The third aspect may involve: the at least one measurementreport including: a first set of measurement information for at leastone cell connected to the first type of core network; and a second setof measurement information for at least one other cell connected to thesecond type of core network. The third aspect may involve the selectionbeing based on an indication that the serving base station for thestandalone mode of operation is to be the secondary base station for thenon-standalone mode of operation. The third aspect may involve theindication being received via a handover request message. The thirdaspect may involve the message including an indication that the servingbase station is to use, for the non-standalone mode of operation, atleast one data radio bearer that was used for the standalone mode ofoperation. The third aspect may involve the message including anindication that the serving base station is to use, for thenon-standalone mode of operation, security information that was used forthe standalone mode of operation. The third aspect may involve themessage including a handover request acknowledgement message. The thirdaspect may involve the message including an addition request message.The third aspect may include electing to send configuration informationto the serving base station via a handover request acknowledgmentmessage instead of an addition request message as a result of theselection.

In a fourth aspect, the disclosure may provide an apparatus configuredfor communication that includes a processing circuit and an interfacecoupled to the processing circuit. The processing circuit may beconfigured to: communicate a message for a handover of a user equipmentbetween a standalone mode of operation and a non-standalone mode ofoperation; and hand-over the user equipment from a first type of corenetwork associated with a first type of protocol stack to a second typeof core network associated with a second type of protocol stack as aresult of communicating the message.

In the fourth aspect, the disclosure may provide a method ofcommunication for an apparatus. The method may include: communicating amessage for a handover of a user equipment between a standalone mode ofoperation and a non-standalone mode of operation; and handing-over theuser equipment from a first type of core network associated with a firsttype of protocol stack to a second type of core network associated witha second type of protocol stack as a result of communicating themessage.

In the fourth aspect, the disclosure may provide an apparatus configuredfor communication. The apparatus may include: means for communicating amessage for a handover of a user equipment between a standalone mode ofoperation and a non-standalone mode of operation; and means forhanding-over the user equipment from a first type of core networkassociated with a first type of protocol stack to a second type of corenetwork associated with a second type of protocol stack as a result ofcommunicating the message.

In the fourth aspect, the disclosure may provide a non-transitorycomputer-readable medium storing computer-executable code, includingcode to: communicate a message for a handover of a user equipmentbetween a standalone mode of operation and a non-standalone mode ofoperation; and hand-over the user equipment from a first type of corenetwork associated with a first type of protocol stack to a second typeof core network associated with a second type of protocol stack as aresult of communicating the message.

The fourth aspect may be modified based on one or more of the following.The fourth aspect may involve the handover being from the standalonemode of operation to the non-standalone mode of operation. The fourthaspect may involve the handover being from the non-standalone mode ofoperation to the standalone mode of operation. The fourth aspect mayinvolve: the standalone mode of operation including connectivity with a3rd Generation Partnership Project (3GPP) New Radio (NR) network; andthe non-standalone mode of operation including dual connectivity with a3GPP NR network and at least one other network. The fourth aspect mayinvolve: the first type of core network including a 3rd GenerationPartnership Project (3GPP) Long Term Evolution (LTE) core network; andthe second type of core network including a 3GPP New Radio (NR) corenetwork. The fourth aspect may involve: the message including a handoverrequired message; and the communicating of the message including sendingthe handover required message. The fourth aspect may involve: themessage including a connection reconfiguration message; and thecommunicating of the message including receiving the connectionreconfiguration message. The fourth aspect may involve the messageincluding a handover request message.

Additional Aspects

The examples set forth herein are provided to illustrate certainconcepts of the disclosure. Those of ordinary skill in the art willcomprehend that these are merely illustrative in nature, and otherexamples may fall within the scope of the disclosure and the appendedclaims. Based on the teachings herein those skilled in the art shouldappreciate that an aspect disclosed herein may be implementedindependently of any other aspects and that two or more of these aspectsmay be combined in various ways. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, such an apparatus may be implemented orsuch a method may be practiced using other structure, functionality, orstructure and functionality in addition to or other than one or more ofthe aspects set forth herein.

As those skilled in the art will readily appreciate, various aspectsdescribed throughout this disclosure may be extended to any suitabletelecommunication system, network architecture, and communicationstandard. By way of example, various aspects may be applied to wide areanetworks, peer-to-peer network, local area network, other suitablesystems, or any combination thereof, including those described byyet-to-be defined standards.

Many aspects are described in terms of sequences of actions to beperformed by, for example, elements of a computing device. It will berecognized that various actions described herein can be performed byspecific circuits, for example, central processing units (CPUs), graphicprocessing units (GPUs), digital signal processors (DSPs), applicationspecific integrated circuits (ASICs), field programmable gate arrays(FPGAs), or various other types of general purpose or special purposeprocessors or circuits, by program instructions being executed by one ormore processors, or by a combination of both. Additionally, thesesequence of actions described herein can be considered to be embodiedentirely within any form of computer readable storage medium havingstored therein a corresponding set of computer instructions that uponexecution would cause an associated processor to perform thefunctionality described herein. Thus, the various aspects of thedisclosure may be embodied in a number of different forms, all of whichhave been contemplated to be within the scope of the claimed subjectmatter. In addition, for each of the aspects described herein, thecorresponding form of any such aspects may be described herein as, forexample, “logic configured to” perform the described action.

Those of skill in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those of skill in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the disclosure.

One or more of the components, steps, features and/or functionsillustrated in above may be rearranged and/or combined into a singlecomponent, step, feature or function or embodied in several components,steps, or functions. Additional elements, components, steps, and/orfunctions may also be added without departing from novel featuresdisclosed herein. The apparatus, devices, and/or components illustratedabove may be configured to perform one or more of the methods, features,or steps described herein. The novel algorithms described herein mayalso be efficiently implemented in software and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of example processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample order,and are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The methods, sequences or algorithms described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory. ROM memory,EPROM memory. EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. An exampleof a storage medium is coupled to the processor such that the processorcan read information from, and write information to, the storage medium.In the alternative, the storage medium may be integral to the processor.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects. Likewise, the term “aspects” does not require that allaspects include the discussed feature, advantage or mode of operation.

The terminology used herein is for the purpose of describing particularaspects only and is not intended to be limiting of the aspects. As usedherein, the singular forms “a” “an” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising.” “includes” or “including,” when used herein, specify thepresence of stated features, integers, steps, operations, elements, orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components, orgroups thereof. Moreover, it is understood that the word “or” has thesame meaning as the Boolean operator “OR,” that is, it encompasses thepossibilities of “either” and “both” and is not limited to “exclusiveor” (“XOR”), unless expressly stated otherwise. It is also understoodthat the symbol “/” between two adjacent words has the same meaning as“or” unless expressly stated otherwise. Moreover, phrases such as“connected to,” “coupled to” or “in communication with” are not limitedto direct connections unless expressly stated otherwise.

Any reference to an element herein using a designation such as “first.”“second,” and so forth does not generally limit the quantity or order ofthose elements. Rather, these designations may be used herein as aconvenient method of distinguishing between two or more elements orinstances of an element. Thus, a reference to first and second elementsdoes not mean that only two elements may be used there or that the firstelement must precede the second element in some manner. Also, unlessstated otherwise a set of elements may include one or more elements. Inaddition, terminology of the form “at least one of a, b, or c” or “a, b,c, or any combination thereof” used in the description or the claimsmeans “a or b or c or any combination of these elements.” For example,this terminology may include a, or b, or c, or a and b, or a and c, or aand b and c, or 2 a, or 2 b, or 2 c, or 2 a and b, and so on.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining, and thelike. Also, “determining” may include receiving (e.g., receivinginformation), accessing (e.g., accessing data in a memory), and thelike. Also, “determining” may include resolving, selecting, choosing,establishing, and the like.

While the foregoing disclosure shows illustrative aspects, it should benoted that various changes and modifications could be made hereinwithout departing from the scope of the appended claims. The functions,steps or actions of the method claims in accordance with aspectsdescribed herein need not be performed in any particular order unlessexpressly stated otherwise. Furthermore, although elements may bedescribed or claimed in the singular, the plural is contemplated unlesslimitation to the singular is explicitly stated.

What is claimed is:
 1. An apparatus for communication, comprising: aninterface; and a processing circuit coupled to the interface andconfigured to: transmit a first message indicating that a user equipmentis to be handed-over from a standalone mode of operation, the firstmessage comprising an indication that a serving base station for thestandalone mode of operation is to be a secondary base station for anon-standalone mode of operation; and transmit a second message toconfigure the user equipment for the non-standalone mode of operation.2. The apparatus of claim 1, wherein the first message comprises ahandover required message.
 3. The apparatus of claim 1, wherein thefirst message comprises: a first set of measurement information for atleast one cell connected to a first type of core network; and a secondset of measurement information for at least one other cell connected toa second type of core network.
 4. The apparatus of claim 3, wherein: thefirst set of measurement information comprises 3rd GenerationPartnership Project (3GPP) Evolved Universal Terrestrial Radio Access(E-UTRA) measurement information; and the second set of measurementinformation comprises 3GPP New Radio (NR) measurement information. 5.The apparatus of claim 1, wherein the processing circuit is furtherconfigured to: transmit the first message based on a determination thatthe standalone mode of operation does not provide a particular type ofservice.
 6. The apparatus of claim 5, wherein the particular type ofservice comprises Voice over New Radio (VoNR) service.
 7. The apparatusof claim 1, wherein the processing circuit is further configured to:transmit the first message based on a determination that communicationby the user equipment uses a particular quality of service.
 8. Theapparatus of claim 1, wherein the processing circuit is furtherconfigured to: select the serving base station for the standalone modeof operation as the secondary base station for the non-standalone modeof operation.
 9. The apparatus of claim 8, wherein the selection of theserving base station for the standalone mode of operation as thesecondary base station for the non-standalone mode of operation is basedon at least one measurement report from the user equipment.
 10. Theapparatus of claim 9, wherein the at least one measurement reportcomprises: a first set of measurement information for at least one cellconnected to a first type of core network; and a second set ofmeasurement information for at least one other cell connected to asecond type of core network.
 11. The apparatus of claim 8, wherein theprocessing circuit is further configured to: receive configurationinformation via a handover request acknowledgment message instead of anaddition request message based on the selection of the serving basestation for the standalone mode of operation as the secondary basestation for the non-standalone mode of operation.
 12. The apparatus ofclaim 1, wherein the processing circuit is further configured to: usefirst security information for the standalone mode of operation; receivean indication to use the first security information for thenon-standalone mode of operation; and use the first security informationfor the non-standalone mode of operation based on the receipt of theindication.
 13. The apparatus of claim 1, wherein the processing circuitis further configured to: use at least one first data radio bearer forthe standalone mode of operation; and use the at least one first dataradio bearer for the non-standalone mode of operation based on themessage indicating that the serving base station for the standalone modeof operation is to be the secondary base station for the non-standalonemode of operation.
 14. The apparatus of claim 1, wherein the processingcircuit is further configured to: receive configuration information viaa handover command instead of an addition request based on the messageindicating that the serving base station for the standalone mode ofoperation is to be the secondary base station for the non-standalonemode of operation.
 15. The apparatus of claim 1, wherein the processingcircuit is further configured to perform at least one of: use, for thenon-standalone mode of operation, security information that was used forthe standalone mode of operation; or use, for the non-standalone mode ofoperation, at least one data radio bearer that was used for thestandalone mode of operation.
 16. A method for communication at anapparatus, comprising: transmitting a first message indicating that auser equipment is to be handed-over from a standalone mode of operation,the first message comprising an indication that a serving base stationfor the standalone mode of operation is to be a secondary base stationfor a non-standalone mode of operation; and transmitting a secondmessage to configure the user equipment for the non-standalone mode ofoperation.
 17. The method of claim 16, wherein the first messagecomprises a handover required message.
 18. The method of claim 16,wherein: the standalone mode of operation is associated with a singleradio access technology; and the non-standalone mode of operation isassociated with a plurality of radio access technologies.
 19. The methodof claim 16, wherein: the first message comprises an NG-AP handoverrequired message associated with an inter-system handover from a 5Gsystem to an evolved packet system where a source node is used as atarget secondary node; and the source node comprises a gNB.
 20. A userequipment, comprising: an interface; and a processing circuit coupled tothe interface and configured to: operate in a non-standalone mode ofoperation with a first type of core network; receive a messageindicating that the user equipment is to be handed-over from thenon-standalone mode of operation to a standalone mode of operation witha second type of core network; and operate in the standalone mode ofoperation after receipt of the message.
 21. The user equipment of claim20, wherein: the standalone mode of operation comprises connectivitywith a 3rd Generation Partnership Project (3GPP) New Radio (NR) network;and the non-standalone mode of operation comprises dual connectivitywith a 3GPP NR network and at least one other network.
 22. The userequipment of claim 20, wherein: the first type of core network comprisesa 3rd Generation Partnership Project (3GPP) Fourth Generation (4G) corenetwork; and the second type of core network comprises a 3GPP FifthGeneration (5G) core network.
 23. The user equipment of claim 20,wherein the processing circuit is further configured to: obtain firstcontext information for the non-standalone mode of operation; obtainsecond context information for the standalone mode of operation; andmaintain the first context information and the second contextinformation during handover from the non-standalone mode of operation tothe standalone mode of operation.
 24. The user equipment of claim 23,wherein the processing circuit is further configured to: determine thatthe handover failed; and revert to use of the first context informationbased on the determination that the handover failed.
 25. The userequipment of claim 20, wherein the message comprises a connectionreconfiguration message including standalone mode configurationinformation for the second type of core network.
 26. The user equipmentof claim 20, wherein the processing circuit is further configured to:use first security information for the non-standalone mode of operation;receive an indication via an addition request message to use the firstsecurity information for the standalone mode of operation; and use thefirst security information for the standalone mode of operation based onthe receipt of the indication.
 27. The user equipment of claim 20,wherein the processing circuit is further configured to: send devicecapability bits indicating whether the user equipment supports: handoverfrom the non-standalone mode of operation to the standalone mode ofoperation, handover from the standalone mode of operation to thenon-standalone mode of operation, inter-system handover from thenon-standalone mode of operation to the standalone mode of operation,inter-system handover from the standalone mode of operation to thenon-standalone mode of operation, or any combination thereof.
 28. Theuser equipment of claim 26, wherein: the standalone mode of operation isassociated with a single radio access technology; and the non-standalonemode of operation is associated with a plurality of radio accesstechnologies.
 29. A method for communication at a user equipment,comprising: operating in a non-standalone mode of operation with a firsttype of core network; receiving a message indicating that the userequipment is to be handed-over from the non-standalone mode of operationto a standalone mode of operation with a second type of core network;and operating in the standalone mode of operation after receiving themessage.
 30. The method of claim 29, wherein: the message comprises aradio resource control connection reconfiguration message associatedwith an inter-system handover from an evolved packet system to a 5Gsystem; and a secondary node comprises a gNB.